chore(openspec): drop 9 superseded proposals + 11 stub archive files

Drop 9 batch proposals that are superseded by the boocode-lift-analysis
(boocontext-audit, conductor upgrades, self-healing/verify-gate skills):
add-3tier-memory, import-llm-evaluator, import-pregel-engine, plugin-platform,
conductor-evolution, code-intelligence-upgrade, dev-workflow, ui-overhaul,
agent-reliability.

Delete 11 stub archive files (49-66B each, 'Status: Shipped. Archived.' only)
that provide zero documentation value over the existing CHANGELOG.md + git tags.

openspec/changes/token-analyzer-ui/proposal.md

@@ -0,0 +1,26 @@
+## Why
+
+Token usage data is already accumulated per-session (agent_sessions.input_tokens/output_tokens/cost), per-tool (tool_cost_stats view), and per-task (tasks.token_breakdown JSONB), but there is no dedicated UI to view or analyze it. The only token surface today is the ContextMeter ring and the inline ChatThroughput readout — both per-chat, transient, and ephemeral. Users have no way to audit token consumption across sessions, compare provider costs, or understand where their context budget goes.
+
+## What Changes
+
+1. **Nav button**: Add a "Token Analytics" button to the sidebar nav, above the existing Settings button, linking to a new `/analytics` route.
+2. **Token Analytics page**: A new route/page at `/analytics` showing aggregate token usage across sessions, per-tool cost breakdown, and per-session token history.
+3. **API endpoints**: New or extended read endpoints to serve aggregate token data for the analytics page.
+
+## Capabilities
+
+### New Capabilities
+
+- `token-analytics-dashboard`: Aggregate token usage dashboard page with per-session, per-tool, and per-provider breakdowns. Reuses existing `agent_sessions`, `tool_cost_stats`, and `token_breakdown` data sources.
+- `nav-button-token-analytics`: Sidebar nav button (above Settings) linking to the analytics route.
+
+### Modified Capabilities
+
+*(No existing capabilities have requirement changes — this is net-new.)*
+
+## Impact
+
+- **apps/web/src**: New page (`/opt/boocode/apps/web/src/pages/Analytics.tsx`), new route in App.tsx, new nav button in ProjectSidebar.tsx, new API client methods.
+- **apps/server or apps/coder**: Maybe a new aggregate endpoint if existing routes don't cover the required queries; otherwise reuse existing `/api/tools/cost_stats` and `/api/coder/sessions/:id/agent-sessions` endpoints.
+- **No schema changes** — all data is already persisted.