docs: create v1.9.0 roadmap (3 phases)

Phases:
1. Foundation & Learning: Index store, PostToolUse hook
2. Context Injection: Convention detection, SessionStart hook
3. Brownfield & Integration: analyze-codebase, GSD integration, docs

All 29 v1 requirements mapped to phases.

.planning/STATE.md

@@ -4,39 +4,35 @@
 
 See: .planning/PROJECT.md (updated 2026-01-19)
 
-**Core value:** Same guarantees, 50-70% fewer tokens for simple tasks
-**Current focus:** Planning next milestone
+**Core value:** Claude understands your codebase structure and conventions before it starts working — automatically
+**Current focus:** v1.9.0 Codebase Intelligence System
 
 ## Current Position
 
-Phase: Ready for new milestone
+Phase: 1 of 3 (Foundation & Learning)
 Plan: Not started
-Status: v1.8.0 shipped, ready for next milestone
-Last activity: 2026-01-19 — v1.8.0 Quick Mode milestone complete
+Status: Ready to plan
+Last activity: 2026-01-19 — Roadmap created for v1.9.0
+
+Progress: [░░░░░░░░░░] 0%
 
 ## Performance Metrics
 
 **Velocity:**
-- Total plans completed: 3
-- Average duration: 2.3 min
-- Total execution time: 7 min
+- Total plans completed: 0
+- Average duration: -
+- Total execution time: 0 min
 
 **By Phase:**
 
 | Phase | Plans | Total | Avg/Plan |
 |-------|-------|-------|----------|
-| 1. Core Command | 2/2 | 4 min | 2 min |
-| 2. Documentation | 1/1 | 3 min | 3 min |
+| 1. Foundation & Learning | 0/2 | - | - |
+| 2. Context Injection | 0/2 | - | - |
+| 3. Brownfield & Integration | 0/3 | - | - |
 
 *Updated after each plan completion*
 
-## Quick Tasks Completed
-
-| ID | Name | Commit | Date |
-|----|------|--------|------|
-| 001 | commands-html-page | a1454db | 2026-01-19 |
-| 002 | 90s-html-command-reference | fc3287c | 2026-01-19 |
-
 ## Accumulated Context
 
 ### Decisions
@@ -54,5 +50,5 @@ None.
 ## Session Continuity
 
 Last session: 2026-01-19
-Stopped at: v1.8.0 milestone complete
+Stopped at: Roadmap created, ready to plan Phase 1
 Resume file: None