chore: complete v1.0 MVP milestone

Archive roadmap, requirements, and phase directories to milestones/.
Evolve PROJECT.md with validated requirements and key decisions.
Reorganize ROADMAP.md with milestone grouping.
Delete REQUIREMENTS.md (fresh for next milestone).

.planning/MILESTONES.md

@@ -0,0 +1,19 @@
+# Milestones
+
+## v1.0 MVP (Shipped: 2026-03-15)
+
+**Phases completed:** 3 phases, 10 plans
+**Timeline:** 2 days (2026-03-14 → 2026-03-15)
+**Codebase:** 5,742 LOC TypeScript, 53 commits, 114 files
+
+**Key accomplishments:**
+- Full gear collection with item CRUD, categories, weight/cost totals, and image uploads
+- Planning threads with candidate comparison and thread resolution into collection
+- Named setups (loadouts) composed from collection items with live totals
+- Dashboard home page with summary cards linking to all features
+- Onboarding wizard for first-time setup experience
+- Complete test suite with service-level and route-level integration tests
+
+**Archive:** `.planning/milestones/v1.0-ROADMAP.md`, `.planning/milestones/v1.0-REQUIREMENTS.md`
+
+---