fix(ui): titlebar tooltips reveal, not repeat, the session name

[Astro-Han]

Summary

The titlebar identity's two hover tooltips repeated what was already on screen: the name chip re-announced the full session name plus a " — 重命名任务" tail, and the "…" button re-announced the whole session name before its own action. Neither added information, and the tail forced the tooltip into multi-line wraps.

A tooltip only earns its hover when it reveals what the surface cannot show. The name chip hides two different things depending on its state, so its tooltip is two-state:

• Name chip — fully visible: the tooltip shows 重命名任务, the click affordance the surface otherwise never advertises; truncated: the tooltip shows exactly the hidden full text (reading the tail of your own title is the missing information then, and … → 重命名 keeps the action reachable). The " — 重命名任务" tail is gone in both states.
• "…" button — tooltip is 任务操作 alone; the session name sits right next to it and stays in its accessible name (label), so screen-reader context is unchanged.
• Read-only (shared-session) title — not clickable, so its native title stays truncation-gated only (full name when ellipsized, none otherwise).

Truncation could not be measured before: .maka-titlebar-identity__segment--session was display: inline, and inline elements always report scrollWidth/clientWidth of 0 — which is also why the old code could not tell whether truncation ever happened. The span now follows the quote-ref-chip recipe (display: block; min-width: 0; max-width: 100%), making the ellipsis real measurable layout; a ResizeObserver keeps the clipped state current across resizes.

No behavior changes beyond the two tooltips: clicking the title still renames, the "…" menu still lists 重命名, accessible names are byte-identical to before.

Name chip, truncated state — light / dark

Name chip, fully visible state — light / dark

(Each row is the same story at the same 1280px viewport, left BEFORE main / right AFTER this branch. The truncated pair's BEFORE fixture name happens to fit, which makes the defect plain: a fully visible title still gets a tooltip that repeats it, twice as long as needed.)

Verification

• New unit test packages/ui/src/__tests__/titlebar-session-identity.test.tsx pins the fake-DOM wiring: accessible names keep the name — action form, the chip always has a tooltip configured, and the read-only branch's native title is truncation-gated; tooltip contents are asserted in the browser tier.
• packages/ui: npm run build + node --test --test-concurrency=4 "dist/**/*.test.js" → 642/643 pass; the 1 failure (prompt-rail-reading-position hover-card assertion) fails identically on a clean main checkout.
• npm --workspace @maka/desktop run typecheck:stories passes.
• apps/desktop: full build-storybook + smoke:storybook — titlebar-identity-truncated (truncated → full-name tooltip, … → 任务操作) and titlebar-project-feedback-narrow (visible → 重命名任务 hint) both pass with their play functions. The one smoke failure, design-system-functional-motion, is a pre-existing animation-timing flake: it fails identically when running the smoke against main's existing storybook-static.
• Root npm run format / npm run lint clean.
• Not run: Electron E2E locally (CI lane); no new E2E needed — the story plays cover the browser-tier behavior.

AI use

Select exactly one:

• No generative tool made a substantive contribution
• Generative tooling made a substantive contribution

Tool(s) and scope: Maka (GLM) — diagnosis, implementation, tests, story plays, and screenshot automation; reviewed locally before commits. Commits carry Generated-by.

Checklist

• Tests cover the change and fail without it
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — described under Summary above

[jackwener]

I reviewed 2cb8eda2a820c8db41d0fbd8d138b4fd762610a3.

No P0–P2.

A tooltip should show what the surface cannot. The name chip now measures real overflow (display: block + ResizeObserver on the rendered span, including after a rename swap). Truncated: tooltip is the hidden full name. Fully visible: tooltip is the rename action. The "…" menu tooltip is 任务操作 only; the session name stays in its accessible name. Read-only titles keep a native title only when clipped.

Hosted test was not waited on.

简体中文

我审查了 2cb8eda2a820c8db41d0fbd8d138b4fd762610a3。没有 P0–P2。

标题栏 tooltip 只揭示表面上看不到的东西：截断给全名，未截断给「重命名任务」；「…」只提示「任务操作」。本审查没有等 hosted test。

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Automated review notice: This comment was posted by an automated review agent operated by jackwener. It is not an independent human review and does not replace one.