chore: archive v1.2 Collection Power-Ups milestone

Archive roadmap and requirements to milestones/, evolve PROJECT.md
with validated requirements, update retrospective, and reorganize
ROADMAP.md with milestone groupings.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.planning/MILESTONES.md

@@ -1,5 +1,23 @@
 # Milestones
 
+## v1.2 Collection Power-Ups (Shipped: 2026-03-16)
+
+**Phases completed:** 3 phases, 6 plans, 11 tasks
+**Timeline:** 3 days (2026-03-14 → 2026-03-16)
+**Codebase:** 7,310 LOC TypeScript, 66 files changed (+7,243 / -206)
+
+**Key accomplishments:**
+- Weight unit conversion (g/oz/lb/kg) with segmented toggle wired across all 8 display call sites
+- Candidate status tracking (researching/ordered/arrived) with clickable StatusBadge popup
+- Sticky search/filter toolbar with text search and icon-aware CategoryFilterDropdown
+- Per-setup item classification (base/worn/consumable) with click-to-cycle badge
+- Recharts donut chart with category/classification toggle, hover tooltips, and weight subtotals
+- Classification-preserving sync that maintains metadata across atomic setup re-sync
+
+**Archive:** `.planning/milestones/v1.2-ROADMAP.md`, `.planning/milestones/v1.2-REQUIREMENTS.md`
+
+---
+
 ## v1.1 Fixes & Polish (Shipped: 2026-03-15)
 
 **Phases completed:** 3 phases, 7 plans