v0.10.0 — Location spine: garden moved onto a shared place tree

Completes the Location feature (schema + migration landed earlier under 98cabc5).

- Hierarchical Location model is the shared spine; unlimited nesting
- Garden add/edit now picks a reusable Location (inline create) instead of
  freeform text; garden groups By Location off the real tree
- Dual-write keeps legacy Plant.zone in sync with location.name (Release A)
- /api/locations CRUD + /api/locations/[id]/log (logs a location + its sub-locations)
- Location tree pure-core (buildTree/computePath/descendantIds) with tests
- Location added to backup/restore export
- Bump APP_VERSION 0.10.0 + plain-English changelog entry

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/changelog.ts

@@ -8,6 +8,13 @@ export type ChangelogEntry = {
 };
 
 export const CHANGELOG: ChangelogEntry[] = [
+  {
+    version: "0.10.0",
+    date: "2026-06-15",
+    changes: [
+      "Locations are now real, reusable places instead of just typed-in text. Pick where a plant lives from your saved spots, or add a new one on the fly — and the same locations will soon hold your tools, pantry, and more. Your existing plant locations carried over automatically.",
+    ],
+  },
   {
     version: "0.9.1",
     date: "2026-06-15",