feat(jira): Browse Jira — manual project-first discovery surface (Slice 5)

[f1uke]

Slice 5 — Browse Jira (the last slice of the approved Jira build)

An entry point ◈ Browse Jira sits next to + New task. It opens a full-page surface (mockup 02) where you:

1. Pick a Jira project first — a searchable dropdown of your real project list (GET /jira/projects), with a "Last used" chip; the pick is remembered across visits (localStorage ao.jira.lastProject).
2. Search/pick a Story within that project — issues list live (GET /jira/search, project-scoped; lists recent issues with no text typed, narrows as you type). Client-side type filter chips (All / Story / Bug / Sub-task / Support).
3. Create session ▷ — hands off to the existing New task modal pre-filled with the issue (mockup 03), creating a worker bound to jira:<KEY>.

Manual + read-only by design — nothing auto-imports onto the board; the one write is the create.

Reuse, not rebuild

Reuses the Slice-4 REST endpoints (GET /jira/search, GET /jira/projects) — no new backend, frontend only. api-drift is untouched.

Changes

• useJiraProjects hook + mockJiraProjects; generalized useJiraSearch to fire when a project is scoped (empty text lists a project's issues) — the New-task/link pickers pass project="" so their 2-char gate is unchanged.
• JiraProjectPicker — searchable dropdown, Last-used chip, remembers the pick.
• BrowseJiraPage + un-nested route _shell.projects.$projectId_.jira (same trailing-_ pattern as project settings; regenerated routeTree.gen.ts).
• NewTaskDialog gains an optional initialIssue (the Browse handoff).
• ShellTopbar "Browse Jira" button (active state on the surface).

Deliberate scope trims (would need new backend / current-user)

• Subtask expand rows under a Story — needs a non-session issue-detail-with-subtasks endpoint we don't have; the design note itself says subtasks are context-only. Omitted.
• "Assigned to me" chip — needs current-user resolution the reused endpoints don't provide. Omitted rather than ship dead UI.

Verification

• typecheck clean; full vitest 856 passed (+13 new across BrowseJiraPage / JiraProjectPicker / ShellTopbar / NewTaskDialog); prettier@3.9.5 clean.
• All fixtures synthetic (DEMO-/ACME- keys, example.atlassian.net). Matches mockup 02.

Live behavior (project list, in-project search, create-from-Jira) needs a Jira API token and is covered by the attached smoke checklist.

🤖 Generated with Claude Code