docs: archive stale mission state, scaffold CLI unification mission

Prior sessions left three different missions spread across the docs:
- docs/MISSION-MANIFEST.md: Harness Foundation (complete)
- docs/TASKS.md: Storage Abstraction Retrofit (P1-P4 done, P5 pending)
- docs/scratchpads/mvp-20260312.md: MVP mission (stale)

Reset the working state to a single clean mission focused on what
actually needs to happen next: unify the mosaic CLI, add first-class
commands for every sub-package, fix the gateway bootstrap token
recovery dead-end, and stitch the install UX end-to-end.

Changes:
- Move Harness Foundation manifest + PRD to docs/archive/missions/harness-20260321/
- Move Storage Abstraction TASKS.md to docs/archive/missions/storage-abstraction/
- Scaffold new docs/MISSION-MANIFEST.md for cli-unification-20260404
  with 8 milestones (M1 done via PR #398, M2 in-progress via this PR)
- Scaffold new docs/TASKS.md with per-milestone task breakdown,
  dependencies, agent assignments, and token estimates
- Scaffold docs/scratchpads/cli-unification-20260404.md with full
  planning decisions, gateway bootstrap bug root cause analysis,
  telemetry architecture notes, and open risks

Left intact:
- docs/PRD.md (v0.1.0, 1005 lines) — still the long-term target
- docs/PRD-TUI_Improvements.md — active TUI work
- docs/scratchpads/* historical task scratchpads — append-only breadcrumbs

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

docs/archive/missions/harness-20260321/MISSION-MANIFEST.md

@@ -0,0 +1,70 @@
+# Mission Manifest — Harness Foundation
+
+> Persistent document tracking full mission scope, status, and session history.
+> Updated by the orchestrator at each phase transition and milestone completion.
+
+## Mission
+
+**ID:** harness-20260321
+**Statement:** Transform Mosaic Stack from a functional demo into a real multi-provider, task-routing AI harness. Persist all conversations, integrate frontier LLM providers (Anthropic, OpenAI, OpenRouter, Z.ai, Ollama), build granular task-aware agent routing, harden agent sessions, replace cron with BullMQ, and design the channel protocol for future Matrix/remote integration.
+**Phase:** Complete
+**Current Milestone:** All milestones done
+**Progress:** 7 / 7 milestones
+**Status:** complete
+**Last Updated:** 2026-03-22 UTC
+
+## Success Criteria
+
+- [x] AC-1: Send messages in TUI → restart TUI → resume conversation → agent has full history and context
+- [x] AC-2: Route a coding task to Claude Opus 4.6, a simple question to Haiku, a summarization to GLM-5 — all via granular routing rules
+- [x] AC-3: Two users exist, User A's memory searches never return User B's data
+- [x] AC-4: `/model claude-sonnet-4-6` in TUI switches the active model for subsequent messages
+- [x] AC-5: `/agent coding-agent` in TUI switches to a different agent with different system prompt and tools
+- [x] AC-6: BullMQ jobs execute on schedule, failures retry with backoff, admin can inspect via `/api/admin/jobs`
+- [x] AC-7: Channel protocol document exists with Matrix integration points defined, reviewed, and approved
+- [x] AC-8: Embeddings run on Ollama local models (no external API dependency for vector operations)
+- [x] AC-9: All five providers (Anthropic, OpenAI, OpenRouter, Z.ai, Ollama) connect, list models, and complete chat requests
+- [x] AC-10: Routing transparency — TUI displays which model was selected and the routing reason for each response
+
+## Milestones
+
+| #   | ID     | Name                               | Status | Branch | Issue     | Started    | Completed  |
+| --- | ------ | ---------------------------------- | ------ | ------ | --------- | ---------- | ---------- |
+| 1   | ms-166 | Conversation Persistence & Context | done   | —      | #224–#231 | 2026-03-21 | 2026-03-21 |
+| 2   | ms-167 | Security & Isolation               | done   | —      | #232–#239 | 2026-03-21 | 2026-03-21 |
+| 3   | ms-168 | Provider Integration               | done   | —      | #240–#251 | 2026-03-21 | 2026-03-22 |
+| 4   | ms-169 | Agent Routing Engine               | done   | —      | #252–#264 | 2026-03-22 | 2026-03-22 |
+| 5   | ms-170 | Agent Session Hardening            | done   | —      | #265–#272 | 2026-03-22 | 2026-03-22 |
+| 6   | ms-171 | Job Queue Foundation               | done   | —      | #273–#280 | 2026-03-22 | 2026-03-22 |
+| 7   | ms-172 | Channel Protocol Design            | done   | —      | #281–#288 | 2026-03-22 | 2026-03-22 |
+
+## Deployment
+
+| Target               | URL       | Method                     |
+| -------------------- | --------- | -------------------------- |
+| Docker Compose (dev) | localhost | docker compose up          |
+| Production           | TBD       | Docker Swarm via Portainer |
+
+## Coordination
+
+- **Primary Agent:** claude-opus-4-6
+- **Sibling Agents:** sonnet (workers), haiku (verification)
+- **Shared Contracts:** docs/PRD-Harness_Foundation.md, docs/TASKS.md
+
+## Token Budget
+
+| Metric | Value  |
+| ------ | ------ |
+| Budget | —      |
+| Used   | ~2.5M  |
+| Mode   | normal |
+
+## Session History
+
+| Session | Runtime         | Started    | Duration | Ended Reason | Last Task         |
+| ------- | --------------- | ---------- | -------- | ------------ | ----------------- |
+| 1       | claude-opus-4-6 | 2026-03-21 | ~6h      | complete     | M7-008 — all done |
+
+## Scratchpad
+
+Path: `docs/scratchpads/harness-20260321.md`