Rewrite sessions-commands-events in a direct, guide-appropriate voice

[mmacy]

Two prose-only passes over docs/guides/sessions-commands-events.md. No code block changed: every fenced block is byte-identical to main (verified by diffing extracted fences against origin/main).

Pass 1 — voice rewrite (declaw)

Cut the AI-voice tells while keeping the guide-interior register:

• Design justifications and asides the text already states: "A rejected command is a normal outcome, not a failure", "A referee correcting the world doesn't stop just because the party fell...", "because an objective the party finished is one the party can be told about", "One asymmetry is deliberate", "For the same reason... which is why a hand-driven completion grants nothing", "That's the additive-schema guarantee in practice" (the contract is named in determinism-saves-replay.md), the "referee typo" rationale, "isn't even worth a typed exception", "None of these are in-fiction outcomes. They tell you...".
• Hedge/filler: "not a side effect", "deliberately tolerant", "on purpose", "A handful", the coined "validate-then-mutate" label, "It's total and pure" -> "It never raises".
• Metaphor/throat-clearing: "The modes form a loop with two ways out" removed.
• Over-explained restatements compressed ("contains exactly the facts" -> "carrying the facts"; "which is what makes X answerable" -> "so X is answerable").

Kept as deliberate terminology: headings and anchors, the quoted example questions ("why did the party get that item?", "has this session ended?"), exactly one entrance, spawn as the name of the command family.

Pass 2 — concision (subagent pass, reviewed)

Merged sentences that restated the same fact (the "exactly one way to mutate" guarantee, the untouched-session/only-clears-every-check pair, "a lost battle is not the only way" into the game_over sentence) and cut flabby constructions ("previously-dumped", "what the visibility field means", "for how you author", double "with... with the clock"). No fact added, dropped, or altered; all API names, codes, links, and anchors intact.

One deviation from the pass brief, flagged for review: "seven referee commands" became "a family of referee commands" — AGENTS.md forbids numeric surface counts in prose, and the sibling listeners-and-flags page states the same partition without a total. The count is derivable from the "Three of them... the other four" partition that follows.

Verification

• Fenced blocks diffed against origin/main: identical
• uv run pytest tests/test_docs_examples.py — 319 passed, 73 skipped (no-run blocks)
• uv run mkdocs build --strict — clean

Review locally at http://127.0.0.1:8001/osrlib-python/guides/sessions-commands-events/ (mkdocs serve with livereload is running).