refactor(components): extract useWorkspaceClipboardPacks + useGuidedRunbook

[saagpatel]

What

Two follow-up DraftTab extractions:

• `useWorkspaceClipboardPacks` — the three handoff/evidence/KB-draft clipboard handlers (`handleCopyHandoffPack`, `handleCopyEvidencePack`, `handleCopyKbDraft`). ~100 LOC of handler + deps out of the shell.
• `useGuidedRunbook` — the four guided-runbook callbacks (`handleStartGuidedRunbook`, `handleAdvanceGuidedRunbook`, `handleCopyRunbookProgressToNotes`, `handleGuidedRunbookNoteChange`) plus the `guidedRunbookNote` state. ~170 LOC of handler + deps out of the shell.

Shell reduction: 2127 → 1893 LOC (-234, ~11% on this PR).

Why

These are the two cleanest remaining hook concerns in DraftTab that don't cross-cut the draft-content state web (response / sources / metrics / confidence / grounding / caseIntake). Each is self-contained with a short argument list. Extracting them is low-risk and brings the shell materially closer to the ≤1000 LOC Wave 5 success target (now at 1893).

The bigger remaining extraction, `useDraftPersistence` (wrapping `handleSaveDraft` + `handleLoadDraft` + autosave), touches 20+ shell state setters and was deferred in the verification pass — it deserves its own PR rather than a parallel teammate.

How

1. Create `useWorkspaceClipboardPacks.ts` with the three copy handlers. Hook takes pack memos + saveCaseOutcome + logEvent + handoff-touched callback + toast callbacks.
2. Create `useGuidedRunbook.ts` with the four callbacks. Hook owns `guidedRunbookNote` state; takes the ops callbacks (start/advance/addEvidence), the shell's workspace-level setters (diagnostic notes, panel density, runbook session scope/touched), and toast callbacks.
3. Update `DraftTab.tsx` to consume both hooks. Reorder the guided-runbook hook call earlier in the component body so `buildDiagnosisJson`'s dep array can reference `guidedRunbookNote`.
4. Add `useWorkspaceClipboardPacks.test.ts` (4 tests) and `useGuidedRunbook.test.ts` (5 tests).

Testing

• `pnpm tsc --noEmit` — clean.
• `pnpm test` — 214 pass (was 205; +9 new hook tests across 2 files).
• `pnpm ui:gate:static` — exit 0.

Risk / Notes

• `DraftTabHandle` interface unchanged (still pinned by `DraftTab.handle.test.tsx`).
• Behavior preserved: clipboard flow, guided-runbook start/advance/copy flow, note-change touched-tracking, all identical.
• DraftTab.tsx still over the 700-LOC target — Wave 5 per-file targets documented as aspirational; success criterion of "no file >1000 LOC" remains the focus.