chore(orchestrator): rescope Phase 7 as Feature Completion, add Phase 8

Phase 7 was underscoped as "Polish & Beta" but the platform isn't
feature-complete. Based on E2E testing feedback:

Phase 7 → "Feature Completion (v0.0.8)" with 17 tasks:
- 6 new web UI tasks (P7-009–P7-014): chat, conversations, projects,
  providers, settings, admin
- 3 agent tasks (P7-015–P7-017): tool expansion, MCP client, skills
- 2 CLI tasks (P7-018–P7-019): model switching, session management
- 1 architecture task (P7-020): coord DB migration

Phase 8 → "Polish & Beta (v0.1.0)" with deferred tasks:
- Additional SSO/LLM providers, performance, release gate

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/MISSION-MANIFEST.md

@@ -8,10 +8,10 @@
 **ID:** mvp-20260312
 **Statement:** Build Mosaic Stack v0.1.0 — a self-hosted, multi-user AI agent platform with web dashboard, TUI, remote control, shared memory, mission orchestration, and extensible skill/plugin architecture. All TypeScript. Pi as agent harness. Brain as knowledge layer. Queue as coordination backbone.
 **Phase:** Execution
-**Current Milestone:** Phase 7: Polish & Beta (v0.1.0)
-**Progress:** 7 / 8 milestones
+**Current Milestone:** Phase 7: Feature Completion (v0.0.8)
+**Progress:** 7 / 9 milestones
 **Status:** active
-**Last Updated:** 2026-03-14 UTC
+**Last Updated:** 2026-03-15 UTC
 
 ## Success Criteria
 
@@ -38,7 +38,8 @@
 | 4   | ms-161 | Phase 4: Memory & Intelligence (v0.0.5) | done        | —      | —     | 2026-03-13 | 2026-03-13 |
 | 5   | ms-162 | Phase 5: Remote Control (v0.0.6)        | done        | —      | #99   | 2026-03-14 | 2026-03-14 |
 | 6   | ms-163 | Phase 6: CLI & Tools (v0.0.7)           | done        | —      | #104  | 2026-03-14 | 2026-03-14 |
-| 7   | ms-164 | Phase 7: Polish & Beta (v0.1.0)         | not-started | —      | —     | —          | —          |
+| 7   | ms-164 | Phase 7: Feature Completion (v0.0.8)    | not-started | —      | —     | —          | —          |
+| 8   | ms-165 | Phase 8: Polish & Beta (v0.1.0)         | not-started | —      | —     | —          | —          |
 
 ## Deployment