Tasks: one verbosity switch over the whole trace, defaulting to quiet

The last spec artifact. Derived from design.md and testing-plan.md. Gate-less (issue-281): it advances on shape.

Execution DAG

Tasks

[x] 1 · The two predicates. In ui/src/api/model.ts, export isReadable(row) and isBookkeeping(event) per design.md § Components. Write the classification table as tests in ui/src/api/model.test.ts first, watch them fail, then implement. Requirements: R1.2, R1.3, R1.4, R2.1, R2.2. Test: testing-plan T1, T8.
[x] 2 · The switch reaches every row. In ui/src/components/Transcript.tsx, rename TranscriptView's showTools to verbose with default false, filter the projected rows through isReadable, and add EventTrail, HiddenNote and the exported VERBOSE_LABEL. Extend ui/src/components/Transcript.test.tsx red-first. Requirements: R1.1, R1.2, R3.1, R4.1, R4.2, R4.3. Test: testing-plan T2.
[x] 3 · The panel. In ui/src/views/WorkItemDetail.tsx, initialise the state false, rename it, put VERBOSE_LABEL in the visible copy and the aria-label, add the explanatory title, and hand the fallback's events to EventTrail. Requirements: R1.1, R3.2, R4.1. Test: testing-plan T4, T9.
[x] 4 · The dashboard tests. Update ui/src/App.test.tsx for the new default, the new copy and the keyboard path, and assert that the quiet stream still carries the agent's prose and the malformed line. Requirements: R1.1, R2.3, R3.1, R3.2, R3.3. Test: testing-plan T4, T9, T10.
[x] 5 · The capability doc. Update docs/capabilities/control-plane.md so the trace panel's description names the switch by its new name and its whole-stream scope. Requirements: R3.2. Test: testing-plan T12.
[x] 6 · Verify and record. Run the matrix, capture the T5 browser pass or its reason, and write evidence/verification.md, self-review.md, security-review.md and documentation.md. Requirements: all. Test: testing-plan T1–T12.