docs+openspec: prior-art research (Organic Maps, Endurain, wanderer) and 15 proposals

Add docs/inspirations.md as the durable record of the 2026-07-05/06
prior-art research — per-project learnings with source paths, canonical
credit lines, and the changes each spawned — and extend the
acknowledgment lists in philosophy.md/architecture.md (Organic Maps,
Endurain, wanderer).

New OpenSpec changes (proposal/design/specs/tasks each):
- Organic Maps: elevation-profile-hardening, gpx-parser-robustness,
  hiking-time-estimate, poi-index, hiking-foot-profile
- Endurain: account-export, activity-duplicate-review,
  fit-parsing-hardening, activity-locations, self-hosting-guide,
  activity-privacy-controls
- wanderer: federation-hardening, link-share-tokens
- credits-page (user-visible acknowledgments)

Updated in-flight changes with wanderer prior-art sections:
route-federation, route-discovery.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

openspec/changes/activity-locations/tasks.md

@@ -0,0 +1,22 @@
+## 1. Geocode package
+
+- [ ] 1.1 Create `packages/geocode`: build script converting GeoNames `cities500` TSV → compact artifact (name, admin1, country, lat, lon), checked in with CC-BY attribution/license file
+- [ ] 1.2 Implement `nearestPlace(lat, lon)` with a 1°-grid index + neighbor scan; distance thresholds (30 km place / 200 km country) as constants; measure load time + resident memory and record in the package README
+- [ ] 1.3 Unit tests: city center, border town, mid-ocean (country-only/none), poles/antimeridian edge cells
+
+## 2. Schema & derivation
+
+- [ ] 2.1 Add `location_name` + `location_country` to `activities` and `routes` + migration
+- [ ] 2.2 Derive in the gpx-save shared step from the first geometry point for all local creation paths; skip remote/federated ingest
+- [ ] 2.3 One-shot idempotent pg-boss backfill job over rows with geometry and null label
+
+## 3. Display
+
+- [ ] 3.1 Detail pages + feed/list cards render the label (place + localized country name via i18n); null renders nothing
+- [ ] 3.2 Masking: render the label only where the viewer can see the geometry (shared visibility path); coordinate with `activity-privacy-controls` flag if landed
+- [ ] 3.3 Add GeoNames attribution to the journal credits alongside OSM attribution; update the privacy manifest (derived on-instance, no third parties)
+
+## 4. Verification
+
+- [ ] 4.1 E2E: import a fixture GPX → label appears on detail + feed; private activity's label invisible to another user
+- [ ] 4.2 Run `pnpm typecheck && pnpm lint && pnpm test && pnpm test:e2e`