feat(assistant): refine conversation, reasoning and artifact workflows

docs/explorations/2026-10-20-assistant-layout-acceptance.md

@@ -2,6 +2,10 @@
 
 Date: 2026-10-20
 
+> Historical record. The owner rejected the history density and top-level Back hierarchy.
+> The [October 21 correction and actual rendered acceptance](2026-10-21-assistant-navigation-and-density-acceptance.md)
+> supersede the heading lane, history target extension and command sizing below.
+
 ## Result and scope
 
 The assistant now shares a 16px content rail across its header, onboarding, Models,

docs/explorations/2026-10-21-assistant-conversation-craft.md

@@ -0,0 +1,47 @@
+# Assistant conversation and artifact craft acceptance
+
+Accepted runtime source: `d6c0411372e168a5a1c124c82408b7499e7e3cc2`.
+Build SHA-256: `23a96f4182123707557f63f43762b563cdfcd91f25f9a9aaccb20561081123b0`.
+Upstream ran source: `72c44840707ee5dc88a3e60e5a4906f73a7fc98d` ([PR436](https://github.com/chaxus/ran/pull/436)).
+Subsequent documentation/media commits do not change this accepted runtime.
+
+## Result and ownership
+
+One compact header owns Chat/home, Artifacts, Conversations, New and Close. Sources belongs beside composition; selected model/settings belongs below it. Returning preserves the displayed conversation, draft, selection and reading position. The content spine is 16px. Fine-input header height is 40px; coarse-input height is 52px with 44px targets. Narrow touch composition separates tools and execution into stable rows, keeping voice language readable while Stop and Send coexist.
+
+Only explicitly returned public reasoning enters native `r-reasoning`. It stays transient and bounded at 64 KiB UTF-8 per run, respects reader disclosure, and is excluded from answer copy, history/artifacts, document review and later provider context. No provider thinking defaults, model defaults or storage formats changed. The upstream correction keeps the open header quiet; a documented pnpm patch consumes it locally.
+
+Artifacts open in Preview. Explicit Edit owns the canonical draft; Preview does not save it. Multiline AI comparisons show separately labeled Original/Proposed text, bounded keyboard-scrollable regions and Show full. Short replacements retain inline differences. Acceptance updates an unsaved draft; Save version persists it. Dirty confirmation, stale results, cancellation, export, nearby deletion confirmation and native document review keep their existing owners.
+
+Industry references informed task placement and progressive disclosure, not branding, exact timings or parity claims: [Claude artifacts](https://support.claude.com/en/articles/17153992-what-are-artifacts-and-how-do-i-use-them), [ChatGPT navigation](https://help.openai.com/en/articles/10056348-finding-your-chats-projects-and-files-in-chatgpt).
+
+## Actual visual acceptance
+
+The local report contains 108 unmodified application screenshots: 27 states in four environments. They cover desktop English light, desktop English dark/reduced motion, 320px Portuguese touch/light, and 360px Portuguese touch/dark/reduced motion. All use the production build and deterministic public-provider NDJSON, without injected product CSS.
+
+Four actual recordings cover waiting, reasoning, streaming/completion, Stop/error, reader scrolling, history, artifact preview/edit/unsaved/version save, delete/export, format-limit recovery into native document review, and AI generation/suggestion/acceptance/explicit save. Scrolled narrow captures expose proposed text and acceptance controls. Independent review inspected the complete initial inventory, critical originals and decoded frames, then rechecked corrected comparisons and all four updated recordings.
+
+Native header pointer clicks 60ms apart interrupt the normal disclosure transition. Desktop height reverses before closing (minimum 63.71875px; closed 32px), as does touch (minimum 75.71875px; closed 44px). Reduced motion reaches discrete 32/44px states without intermediate heights. These are measured component results, not competitor timings. Brief closing-body/header overlap is an outgoing transition; the steady open header has no repeated summary.
+
+[Original panes, recordings and provenance](../media/assistant-conversation-craft/) are committed as representative evidence. The complete inventory remains in the local acceptance report.
+
+- [Normal desktop walkthrough](../media/assistant-conversation-craft/desktop-light.webm)
+- [Reduced-motion desktop walkthrough](../media/assistant-conversation-craft/desktop-dark-reduced.webm)
+- [320px touch walkthrough](../media/assistant-conversation-craft/pt-320-touch-light.webm)
+- [360px reduced-motion touch walkthrough](../media/assistant-conversation-craft/pt-360-touch-dark.webm)
+
+![Readable multiline comparison](../media/assistant-conversation-craft/artifact-suggestion-review-desktop-light.png)
+![Touch composer with readable language and separate Stop/Send](../media/assistant-conversation-craft/waiting-pt-320-touch-light.png)
+
+## Verification
+
+- Final runtime: 255 unit files, 6,878 tests passed.
+- Assistant browser coverage: 125 executed cases verified across full and affected runs; three existing conditional skips. Final affected run: 37/37 passed, including unchanged XLS/PPT overflow assertions, layout rails, touch execution, revisions, sources/imports, keyboard return and workspace states.
+- Final comparison/related unit subset: 77 passed. TypeScript, archive-aware lint, Prettier and immutable evaluation-archive checks passed. Production build passed with the identity above.
+- Docker configuration passed using installed standalone `docker-compose -f docker-compose.yaml config --quiet`; the local Docker CLI lacks its compose subcommand. This does not claim a local Docker-image run.
+- Upstream reasoning: 34 unit, 76 SSR and 10 Chromium/WebKit browser cases passed. Guidance/documentation/link/design checks passed; earlier guidance acceptance remains in PR436.
+- Independent spec/code reviews and final screenshot/decoded-recording review approved this runtime.
+
+## Limits and remaining observation
+
+Fixtures prove UI behavior and isolation, not real-model quality or competitor parity. Native Word insertion still rejects Markdown tables; the recording demonstrates localized plain-text recovery and a subsequent valid native review. No document changes without acceptance. Artifact-related failures still use Chat error/recovery presentation; clearer artifact association remains a nonblocking P3 observation. Package publishing and merging are outside this acceptance.

docs/explorations/2026-10-21-assistant-header-and-alignment.md

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+# Assistant header and visible-content alignment
+
+Date: 2026-10-21
+
+Header/alignment figures below record `681e4f9`. The expanded-workflow follow-up at the end
+records the later spacing, target and focus corrections. These are scoped acceptance records,
+not a claim that overall visual hierarchy or motion has reached a final design.
+
+The previous header gave the assistant identity and every destination substantial visual weight.
+History headings started at 16px, while the saving checkbox and command icons started at 24px.
+Equal button frames therefore did not establish a shared leading-content spine.
+
+## Result and ownership
+
+The [application design contract](../design-system.md#assistant-header-and-settings-commands)
+owns the current dimensions and control roles. Five named destinations remain directly available;
+New, Close, nested artifact navigation, drafts and history state retain their existing owners.
+
+| Measured relationship                                   | Before         | Current        |
+| ------------------------------------------------------- | -------------- | -------------- |
+| Fine-input title row / complete header and navigation   | 56 / 97px      | 40 / 77px      |
+| Coarse-input title row / complete header and navigation | 60 / 113px     | 52 / 101px     |
+| Heading, saving checkbox and command icon viewport      | 16 / 24 / 24px | 16 / 16 / 16px |
+| Command label and associated saving status              | 48px           | 40px           |
+| Command target height, fine / coarse input              | 32 / 44px      | 32 / 44px      |
+
+Values are CSS pixels from the pane's inside border edge. The click surface uses 8px of the
+existing gutter; the content spine remains 16px. History rows form a named command-list context
+without repeated resting frames. Framed workflow actions and inputs retain their affordances.
+
+The selected destination has a restrained fill distinct from the actual canvas in both themes,
+with no curved inset underline. Current labels are medium weight; inactive navigation is regular.
+Keyboard focus remains a separate blue outline. Palette properties do not animate on theme changes.
+
+## Industry references
+
+[Linear's 2026 refresh](https://linear.app/now/behind-the-latest-design-refresh) gives supporting
+navigation less emphasis and makes tabs more compact while retaining predictable headers/actions.
+[Cursor's side-chat and conversation-search update](https://cursor.com/changelog/side-chat)
+keeps creation at the top of chat and provides a dedicated conversation-search route. These inform
+hierarchy and placement; this application uses its existing ran roles and input-density contract.
+
+## Actual browser evidence
+
+The local current report contains 20 before/after pane pairs: Chat, Conversations, Artifacts,
+Sources and Models in English desktop light/dark and Portuguese 320/360px coarse-input variants.
+Four additional screenshots include browser-rendered alignment guides. The red guide marks 16px;
+the blue guide marks the 40px history label/status column only within that control group.
+
+The before pairs isolate header/alignment changes after the initial tab-underline removal. The
+[previous acceptance record](./2026-10-21-assistant-navigation-and-density-acceptance.md) retains
+screenshots of the earlier implementation, including the original selected underline.
+
+| Light header                                                                                                        | Dark header                                                                                                       |
+| ------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------- |
+| <img src="../media/assistant-refinement/header-en-light-1280.png" width="432" alt="Compact light assistant header"> | <img src="../media/assistant-refinement/header-en-dark-1280.png" width="432" alt="Compact dark assistant header"> |
+
+| Light history                                                                                                                                | Dark history                                                                                                                                  |
+| -------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------- |
+| <img src="../media/assistant-refinement/history-en-light-1280.png" width="320" alt="Current light history pane with shared leading content"> | <img src="../media/assistant-refinement/history-en-dark-1280.png" width="320" alt="Current dark history pane with visible resting selection"> |
+
+[320px touch alignment guides](../media/assistant-refinement/history-guides-pt-light-320.png),
+[360px dark touch pane](../media/assistant-refinement/history-pt-dark-360.png),
+[Chat](../media/assistant-refinement/chat-en-light-1280.png),
+[Artifacts](../media/assistant-refinement/artifacts-en-light-1280.png),
+[Sources](../media/assistant-refinement/sources-en-light-1280.png), and
+[Models](../media/assistant-refinement/models-en-light-1280.png) show the same current chrome.
+Representative [before history](../media/assistant-refinement/before-history-en-light-1280.png)
+and [before Chat](../media/assistant-refinement/before-chat-en-light-1280.png) are retained.
+[Measured history variants](../media/assistant-refinement/measurements.json) record the actual
+coordinates and header heights, including the effective theme and selected fill.
+
+## Header verification at `681e4f9`
+
+- The independent page spine is 16px. Before the CSS correction, the cross-region assertion
+  failed with the command icon at 24px. It no longer accepts equal but separately inset groups.
+- Chromium: 14 navigation, layout-rail and history-action cases passed, retries disabled. Covers
+  wrapping, resize, hover/press/disabled, contrast, accessible names, focus/confirmation, export,
+  touch targets and rejection/restoration of deliberate geometry defects.
+- WebKit: all four navigation/craft variants passed, retries disabled, including 320/360px touch.
+- Selected fill and shadow are checked after moving the pointer away. Hover cannot supply the
+  selected affordance being verified. The fill must differ from the actual pane canvas.
+- Transparent history rows use the actual pane background for text-contrast measurement;
+  hover/pressed rows use their painted surface. Deletion and focus checks remain in place.
+- The design-token contract and changed-file formatting passed. The production preview was
+  rebuilt from the changed styles; screenshots use that build, not temporary product overrides.
+
+One intermediate run timed out while waiting for the native editor to become ready during
+concurrent screenshot capture. The subsequent complete serial run passed 14/14 with no retries,
+timeout increases or weakened tolerances. Firefox, native browser zoom and real model downloads
+are not claimed as verified by this focused UI correction.
+
+## Expanded-workflow follow-up
+
+Actual production-browser inspection found attachment helper gap 0, model helper gap 17
+(including inline-host baseline space), helper/action gap 12 and adjacent custom-field gap 0.
+The corrected relationships are 8/8/16/16. Artifact confirmation actions now retain 8px separation.
+Touch Chat starters measured 34.25px and now use the adaptive 44px target role. Source filename
+and Remove text centers differed by 6.58px; their shared label role and density-derived first-line
+padding now align without translating glyphs or changing the expanded excerpt's position.
+
+Keyboard removal moves to the next/previous visible source action or Attach when the filtered
+list is empty. Artifact confirmation focuses Cancel and cancellation returns to Delete, keeping
+the draft. A long artifact case verifies that the safe choice is inside the narrow viewport.
+These owners belong to document; no ran component-internal defect was established.
+
+| Before custom fields                                                                                                                                           | Corrected custom fields                                                                                                                                       |
+| -------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| <img src="../media/assistant-detail-audit/before-models-expanded-bottom-pt-320-touch-light.png" width="280" alt="Custom model fields with no inter-field gap"> | <img src="../media/assistant-detail-audit/models-expanded-bottom-pt-320-touch-light.png" width="280" alt="Custom model fields with sixteen pixel group gaps"> |
+
+[Sources after correction](../media/assistant-detail-audit/source-excerpt-pt-360-touch-dark.png),
+[Models in dark theme](../media/assistant-detail-audit/models-dark.png),
+[touch Chat targets](../media/assistant-detail-audit/chat-pt-320-touch-light.png),
+[artifact confirmation](../media/assistant-detail-audit/artifact-delete-confirmation-pt-320-touch-light.png),
+and [focus return after cancellation](../media/assistant-detail-audit/artifact-delete-cancelled-pt-320-touch-light.png)
+are representative full-pane renders. [Capture measurements](../media/assistant-detail-audit/captures.json)
+list 68 current states across English desktop light/dark and Portuguese 320/360px coarse variants.
+The local report retains 60 before/after pairs and 8 additional keyboard-focus captures.
+
+The new regressions failed before their fixes: two focus unit cases; browser helper/focus cases;
+confirmation gap 0vs8; touch targets 34.25 vs 44 and filename/Remove center drift 6.58 vs 1px tolerance.
+Existing geometry expectations, retries and timeouts were not weakened. Final verification:
+Chromium 31/31; WebKit 4/4 focused detail cases; unit 41/41; production build, TypeScript,
+archive-aware lint, changed-file format and diff checks. See `agent-detail-polish.spec.ts` for
+rendered spacing, physical targets and keyboard continuation; existing workspace/layout/source
+and affordance suites remain in the run.
+
+Overall hierarchy still needs design work: the five persistent destinations give configuration,
+content and history similar prominence, and artifact commands need a tighter relationship to their
+content. Current animation is limited; these static captures disable animation for geometry and
+are not motion acceptance. Native zoom, system text scaling, screen readers and real model
+downloads are outside this focused verification.