Lift useDelayedFlag/createDelayedFlag into @maka/ui (dedupe side-chat running-status timing)

[liuxiaocs7]

Context

Split from the review of #4655 (P3, deferred). The side-chat panel needed the main chat's rising-edge running-status timing — useDelayedFlag + the 200ms delay — but the workbar feature layer cannot import the renderer-legacy use-delayed-flag.ts / model-wait-state.ts (the renderer-architecture gate walls feature code off from legacy). So #4655 added a feature-local copy of useDelayedFlag and a const RUNNING_STATUS_DELAY_MS = 200 to quote-companion-panel.tsx.

That leaves:

• Two authorities for one delay/timing — the panel's copy will drift from the main chat's useDelayedFlag.
• A duplicated literal (200) with no single source of truth.
• No unit-test coverage for the timing on the side-chat path (and, in fact, createDelayedFlag has no fake-timer tests anywhere today).

Proposal

Lift the shared pieces into @maka/ui so both sides import one implementation:

• Move the pure createDelayedFlag (+ DelayedFlag, DelayedFlagScheduler) out of apps/desktop/src/renderer/model-wait-state.ts and the useDelayedFlag React binding out of apps/desktop/src/renderer/use-delayed-flag.ts into a new @maka/ui module; export a shared RUNNING_STATUS_DELAY_MS.
• Update the main chat (use-shell-live-turn.ts) and the side chat (quote-companion-panel.tsx) to import from @maka/ui; delete the feature-local copy + literal.
• Re-export from the legacy modules where needed for back-compat / minimal churn.
• Add fake-timer unit tests for createDelayedFlag in @maka/ui (rising-edge delay, no-flash on a fast drop, immediate fall).

Benefits

• One authority for the running-status timing and delay constant.
• Removes the feature→renderer-legacy walled-off duplication — should take the use-delayed-flag.ts / model-wait-state.ts closure entries off the renderer-architecture ledger.
• Establishes the timing unit-test coverage that's missing today.

Origin: #4655 review by @Astro-Han.

[liuxiaocs7]

Claiming this — I'll open a PR from my fork (liuxiaocs7/maka).

[liuxiaocs7]

take

[liuxiaocs7]

Closing as not planned — blocked by the renderer-architecture monotonic-debt ratchet (details in #4848).

The main chat's consumer use-shell-live-turn.ts is a frozen legacy file; the ratchet forbids it gaining a new @maka/ui dependency, so the lifted module can't become the single authority without first migrating a 4-file legacy closure out of the legacy zone (use-shell-live-turn + model-wait-state + live-turn-snapshot + session-event-health, across shell/@maka/core/@maka/ui, touching ~6 importers + tests). That's disproportionate to de-duplicating a small rising-edge timer.

The feature-local useDelayedFlag copy in quote-companion-panel.tsx stays as the accepted state — the #4655 reviewer already noted that rationale is sound. If use-shell-live-turn is migrated out of the legacy zone for other reasons, folding the timer into @maka/ui becomes trivial then.