fix(protocol): enforce request IDs and params

[dannyward630]

What changed

• Reject non-null request IDs that are not strings or integers with JSON-RPC -32600 and a null response ID.
• Preserve arbitrary-precision integer IDs exactly, including values outside the signed and unsigned 64-bit ranges.
• Preserve LPP's notificationNotSupported response for missing or null IDs.
• Require params to be present and an object, returning -32602 for initialized requests with invalid params.
• Apply notInitialized and alreadyInitialized lifecycle errors before parameter validation.
• Update the transport specification and add normative fixtures plus mock-provider regression tests.

Closes #79.

Validation

• cargo fmt --all --check — passed.
• cargo test --workspace — passed (42 tests).
• cargo clippy -p lpp-mock-provider --all-targets -- -D warnings — passed.
• Release build and fixture validation — passed; 70/70 fixtures validated.
• Focused runtime conformance for large integer IDs, pre-initialize requests, and repeated initialization — passed.
• Full mock-provider conformance on Windows — 64/70 passed. Six existing project-loading cases fail because extended Windows paths are encoded as unsupported file URIs.
• Workspace Clippy on Windows still stops at an existing unnecessary_lazy_evaluations warning in conformance/runner/src/session.rs; the changed mock-provider crate is clean.

[chatgpt-codex-connector]

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