docs(ultraplan-local): add Handover 7 + doc-consistency pins for /ultracontinue

Adds Handover 7 (.session-state.local.json) section to HANDOVER-CONTRACTS.md
documenting the multi-session-resume contract:
- Producers: ultraexecute Phase 8/2.55/4 + helper command + future
  graceful-handoff v2.2 + pre-compact-flush refresh
- Consumer: /ultracontinue (read-only)
- Schema v1: schema_version, project, next_session_brief_path,
  next_session_label, status (5-value enum), updated_at
- Forward-compat: unknown top-level keys silently tolerated (drift-WARN)
- Path: .claude/projects/<project>/.session-state.local.json (gitignored)
- Failure modes mapped to validator error codes

Also updates the validator → handover map and Versioning + Stability
tables to include Handover 7.

Extends tests/lib/doc-consistency.test.mjs with three new pins:
1. HANDOVER-CONTRACTS.md contains Handover 7 section
2. session-state-validator.mjs exposes the standard CLI shim
3. CLAUDE.md mentions /ultracontinue-local

Adds the /ultracontinue-local row to the plugin CLAUDE.md commands table —
minimum viable to keep the existing 'CLAUDE.md commands table mentions
every commands/*.md file' iteration test green. Step 11 (Session 2b) will
expand to full README + CLAUDE.md narrative documentation.

Test suite: 182 → 185 (3 new doc-consistency pins, zero regressions).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

plugins/ultraplan-local/CLAUDE.md

@@ -15,6 +15,7 @@ Deep implementation planning and research with an explicit brief step, specializ
 | `/ultraplan-local` | Plan — brief-reviewer, explore, plan, review. Requires `--brief` or `--project`. Auto-discovers `architecture/overview.md` if present | opus |
 | `/ultraexecute-local` | Execute — disciplined plan/session-spec executor with failure recovery | opus |
 | `/ultrareview-local` | Review — independent post-hoc review of delivered code against the brief. Produces `review.md` with severity-tagged findings (Handover 6) | opus |
+| `/ultracontinue-local` | Continue — resumes the next session of a multi-session ultraplan project. Reads `.session-state.local.json` (Handover 7) and immediately begins executing | opus |
 
 ### /ultrabrief-local modes