v1.2.0

• Add /timeline page: horizontal Gantt-style chart of every change's lifecycle — active bars extend to today with an arrow, archived bars render as fixed segments
• Timeline supports an optional "Group by topic" toggle and "Hide active / Hide archived" filter chips, plus an auto-scaling time axis (daily / weekly / monthly / quarterly ticks based on span)
• Read created: from .openspec.yaml and derive archivedDate from archive folder name; surface lifecycle info in ChangeInfo / ChangeDetail (server payload adds two backwards-compatible fields)
• ChangeList row shows Created Apr 20 · 5d ago for active changes and Created Feb 14 → Archived Feb 22 · 8d for archived ones
• ChangeDetail header gains a lifecycle banner (e.g., Created 2026-02-14 · Archived 2026-02-22 (8 days) or Active for 5 days)
• Dashboard adds two stats cards: Avg lifecycle (archived) and Stale active (>30d)
• VS Code sidebar shows lifecycle days in change descriptions and includes the created date in tooltips
• New @spek/web test runner (npm test -w @spek/web) covers the timeline scale and grouping helpers