openspec: propose profile-weekly-distance (weekly bars)

A 12-week distance bar chart under the profile stats header, viewer-scoped,
built on profile-stats (#539). Design records the same no-cache rationale: one
indexed grouped aggregate over a 12-week slice (≤12 rows), gap-filled in JS.

Validates with `openspec validate --strict`. Specs only; no code.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

openspec/changes/profile-weekly-distance/tasks.md

@@ -0,0 +1,20 @@
+## 1. Aggregate query
+
+- [ ] 1.1 Add `getWeeklyDistance(ownerId, { publicOnly, weeks = 12 })` to `activities.server.ts`: `sum(distance)` grouped by `date_trunc('week', coalesce(started_at, created_at))` over the last `weeks` weeks, viewer-scoped.
+- [ ] 1.2 Gap-fill to a contiguous oldest→newest series with `0` for empty weeks; return `{ weekStart, distance }[]`.
+
+## 2. Loader & view
+
+- [ ] 2.1 Profile loader passes the series (same `publicOnly: !isOwn` scoping; only when content is visible).
+- [ ] 2.2 `WeeklyDistanceChart` component: SVG bars normalized to the max week, per-bar `title` distance (via `stats.ts`), localized label; renders nothing when every week is 0. Mount under `ProfileStats`.
+
+## 3. i18n
+
+- [ ] 3.1 Add `journal.profileStats.weeklyDistance*` (label + per-bar readout) to en + de.
+
+## 4. Tests & checks
+
+- [ ] 4.1 Unit: gap-fill produces 12 contiguous weeks with zeros in the right slots.
+- [ ] 4.2 Component (jsdom): renders 12 bars for a series; nothing when all zero; tallest bar = busiest week.
+- [ ] 4.3 E2E: create activities, assert the weekly chart renders on the profile.
+- [ ] 4.4 `pnpm typecheck && pnpm lint && pnpm test && pnpm test:e2e` green.