feat(ui): render Workspace with Claude Design handoff layout

[saagpatel]

Summary

Ports the Claude Design handoff bundle's Workspace (Draft) layout into the real DraftTab. The previous PR #97 polished the shell chrome but left the tab content on its legacy panels; this PR swaps the tab body for the bundle-matching layout — so the visible Workspace now matches the mockup you approved in Claude Design.

What ships visually

• Ticket header card — avatar, reporter, status, assignee, opened timestamp, priority + intent badges (all sourced from currentTicket + caseIntake).
• 4-step workflow strip — Triage → Classify → Draft → Send with numbered circles, ✓ checkmarks for done stages, and accent-active styling.
• Two-column panels — Query + Context on the left; Response + Sources + Alternatives on the right.
• Query panel — textarea, policy/howto/access/incident intent chips wired to caseIntake.likely_category, Short/Medium/Long segment selector.
• Context panel — audience / tone / urgency / environment selects + Generate / Cancel button with ⌘↵ hint.
• Response panel — ML Intent banner, grounding gauge (tone-swapped for clarify/abstain modes), response meta (tok/s, sources, words, context util, supported-claim count), response body with inline [n] cite pills that drill into the source, action row (save template / regenerate / copy).
• Sources list — ranked entries with file path + heading path + score.
• Alternatives strip — saved alternatives rendered as preview chips with one-click swap.

Implementation

• New src/styles/revamp/claudeDesignWorkspace.css (~700 lines) ports the bundle's workspace.css verbatim, scoped under .cdw so the bundle's generic class names (.panel, .badge, .chip, .btn) don't collide with global styles.
• New src/features/workspace/ClaudeDesignWorkspace.tsx is a pure presenter — consumes state + handlers from the existing DraftTab hooks, no new Tauri IPC.
• DraftTab now renders <ClaudeDesignWorkspace /> as its panels prop inside WorkspaceModeShell, dropping the legacy WorkspacePanels + WorkspaceWorkflowStrip + TicketWorkspaceRail path. Unused hook bindings (approval spinner, first-response tone UI, checklist UI, next-action handlers, similar-cases UI) are trimmed from destructures since their panels are no longer rendered.

What this intentionally drops

Some legacy surfaces were only consumable through the old panels and are not visible in the Claude Design mockup:

• First-response tone controls
• Checklist generator UI
• Approval spinner UI
• Similar-cases compare view
• Next-best-action chip
• Explicit 'Analyze intake' button (intake still runs through intent chips)

These can be re-surfaced in follow-up PRs when the design calls for them. The underlying hooks remain in place.

Test plan

• pnpm ui:typecheck — clean
• pnpm test — 67/67 files, 262/262 tests passing
• All pre-commit guards green (branch name, lint-staged, commitlint, gitleaks)
• Manual: launch app, confirm ticket header + workflow strip + two-column panels render with teal accents + radial-glow shell
• Manual: paste a ticket, press Generate, confirm response body renders with inline cite pills, sources list populates, grounding gauge + intent banner appear

🤖 Generated with Claude Code