Unify thinking disclosure and centralize chat turn state

[ProfSynapse]

Summary

Unify the separate thinking ticker and disclosure into one native accordion. While reasoning arrives, the familiar icon pulses and words type letter by letter with cycling dots and a silver sweep. When reasoning ends, the header settles to a static brain icon and Reasoning. Expansion and reading position survive reconciliation and completion; the circular down-arrow resumes following without overriding the transcript’s independent scroll intent. Tool activity stays in the status bar.

The supporting chat refactor gives each generation one service-owned runtime snapshot. Generation outcome and persistence outcome are separate: a completed response stays completed if saving fails, and Retry save retries storage without repeating model or tool work. Targeted message writes replace routine whole-conversation snapshots, reject deleted targets, and preserve accounting. Generation identity scopes callbacks, queue activity and tool status.

Validation

• Production build passed, including lint, type checking and mobile import reachability.
• Full suite: 489 suites and 6,117 tests passed; 89 tests intentionally skipped.
• Real Obsidian smoke test passed with synthetic provider events through actual services, DOM and persistence: keyboard activation, following/pausing, reconciliation, catch-up and settled state.
• Disposable-vault cache rebuild preserved the saved answer and reasoning through a lower-level repository read.
• Typing and settling regressions proved red before the fix; a live component probe confirmed letters, dots and stable completion.
• User tested and approved the build installed in Professor Synapse.

Boundaries

Failed-save recovery is in memory, not crash recovery. Existing JSONL persistence remains authoritative; no schema or dependency changes. This scopes foreground chat ownership, not all Nexus subsystems.

The full suite still reports a worker teardown warning; a focused UI open-handle check passed. An independent duplicate-name error in existing default-workspace initialization was observed in the disposable vault and is documented for follow-up. Physical mobile hardware was not tested.

Implementation details and reproducible test instructions: docs/plans/thinking-disclosure-implementation-notes.md and tests/manual/thinking-disclosure-e2e.md.