refactor: shrink the renderer's first-load chunk and remove three duplicated authorities

[Astro-Han]

Five simplification-audit findings in the desktop renderer and packages/ui. All internal; no user-visible behavior changes.

This is not a fix for the session-switch jank. The measured session-switch cost (9 long tasks, 717 ms, CLS 0.55) has a different, still-unidentified cause and is tracked separately. What is here is bundle size, one duplicated authority removed, and two boundary escape hatches closed.

Bundle size

The workbar feature barrel statically re-exported WorkbarSurface while workbar-host reaches it through lazy(() => import('./workbar-surface')). Because app-shell imports WorkbarHost from that barrel, the static edge dragged the 917-line surface and its five nested tool panels into the eager chunk — rolldown reported INEFFECTIVE_DYNAMIC_IMPORT.

Two Storybook files did import WorkbarSurface from the barrel. The export moves to the feature's testing entry — already recognized as public by workbar-boundary.test.ts, and imported by nothing that ships — and the stories follow it there.

	before	after
entry chunk	2,245.33 kB (gzip 451.12)	2,166.20 kB (gzip 426.86)
workbar-surface chunk	—	81.31 kB (gzip 25.41)
INEFFECTIVE_DYNAMIC_IMPORT	yes	no

One duplicated authority

assistant-stream and thinking-stream were two implementations of one concept — identical Options/Result shapes, the same redact-append-cap pipeline, the same non-string guard, structurally identical complete paths. They differed only in caps, marker strings, and which end of an over-cap buffer survives, and streaming-display-redaction already parameterizes that as recovery: 'head' | 'tail'.

stream-delta now owns the pipeline. Both modules keep their exported names, cap constants, and option types as thin wrappers. Head-keep's short-circuit on a frozen buffer is now expressed as a property of recovery: 'head', which is what it always was — tail-keep has no fixed point, so it is unaffected.

tool-output-stream is deliberately left alone: it accumulates a chunk array with dedup-by-seq, a different problem.

Two boundary escape hatches

Four workbar files imported ComposerProps through a seven- or eight-level relative path into packages/ui/dist/composer.d.ts, a build artifact. @maka/ui exports the type and all four already import from it.

Two local simplifications

• chat-message-surface: the first two render-phase activation branches called setActivation with a byte-identical literal — now one condition. The snapshot handed to ChatView also dropped a session guard whose else branch was unreachable: every branch reseeds sessionId to activeSessionId, and a render-phase setState re-runs the body before anything commits.
• use-roving-row-focus: the dependency-array-free layout effect (deliberate, and left that way) wrote tabIndex on every row on every render. An identical write still invalidates style and forces synchronous layout — DevTools charged it 224 ms of reflow. It now compares first. This helps the module pages that use the hook (skills, scheduled tasks, MCP); the chat transcript does not use it.

Verification

• npm run format, npm run check:asf-headers, biome lint over the touched trees
• @maka/ui build + full packages/ui test suite
• desktop tsconfig.renderer.json and tsconfig.storybook.json typechecks
• apps/desktop/src/main/__tests__/{assistant,thinking}-stream.test.ts — 12/12
• vite build of the renderer, A/B against the same tree with the barrel export restored
• workbar-boundary.test.ts — 6/6

[Astro-Han]

Reopened as a branch that follows the repo's <type>/<description> convention.