feat(mobile): editable activity title for local activities

Adds edits_json column (migration v3) to store user overrides separately
from detail_json so Option A server re-extraction never clobbers them.

- Tap the title in the detail screen to edit (local activities only, shown
  with a ✎ hint). Saves on keyboard dismiss via onEndEditing.
- Cards and search display user_title ?? title.
- Raw upload: user_title sent to server -> sidecar written so web UI shows
  the correct title (server re-extracts from FIT, which has Karoo's title).
- BAS upload: detail.title overridden before sending, no sidecar needed.

mobile/db/index.ts

@@ -35,4 +35,13 @@ export async function migrateDb(db: SQLiteDatabase): Promise<void> {
   } catch {
     // Column already exists — migration already ran, ignore.
   }
+
+  // Migration v3: edits_json stores user overrides (e.g. {"title": "My title"})
+  // kept separate from detail_json so server re-extraction (Option A) never
+  // clobbers user edits.
+  try {
+    await db.execAsync('ALTER TABLE activities ADD COLUMN edits_json TEXT');
+  } catch {
+    // Column already exists — migration already ran, ignore.
+  }
 }

mobile/db/queries.ts

@@ -13,11 +13,13 @@ export type ActivityRow = {
   synced_at: number | null;
   origin: 'local' | 'remote';
   created_at: number;
+  edits_json: string | null;
 };
 
 export type ActivitySummary = {
   id: string;
   title: string;
+  user_title: string | null;  // from edits_json; takes display priority over title
   sport: string;
   started_at: string;
   distance_m: number | null;
@@ -34,20 +36,11 @@ const PAGE_SIZE = 50;
 export function useActivities(searchQuery = '', limit = PAGE_SIZE): ActivitySummary[] {
   const db = useSQLiteContext();
   const like = `%${searchQuery}%`;
-  const rows = db.getAllSync<{
-    id: string;
-    origin: 'local' | 'remote';
-    synced_at: number | null;
-    title: string;
-    sport: string;
-    started_at: string;
-    distance_m: number | null;
-    duration_s: number | null;
-    elevation_gain_m: number | null;
-  }>(`
+  const rows = db.getAllSync<ActivitySummary>(`
     SELECT
       id, origin, synced_at,
       json_extract(detail_json, '$.title')            AS title,
+      json_extract(edits_json,  '$.title')            AS user_title,
       json_extract(detail_json, '$.sport')            AS sport,
       json_extract(detail_json, '$.started_at')       AS started_at,
       json_extract(detail_json, '$.distance_m')       AS distance_m,
@@ -93,6 +86,7 @@ export function useFilteredActivities(filter: ActivityFilter, limit = PAGE_SIZE)
     SELECT
       id, origin, synced_at,
       json_extract(detail_json, '$.title')            AS title,
+      json_extract(edits_json,  '$.title')            AS user_title,
       json_extract(detail_json, '$.sport')            AS sport,
       json_extract(detail_json, '$.started_at')       AS started_at,
       json_extract(detail_json, '$.distance_m')       AS distance_m,
@@ -194,6 +188,19 @@ export async function deleteActivity(
   return row?.original_path ?? null;
 }
 
+export async function setActivityTitle(
+  db: ReturnType<typeof useSQLiteContext>,
+  id: string,
+  title: string,
+): Promise<void> {
+  await db.runAsync(
+    `UPDATE activities
+     SET edits_json = json_set(COALESCE(edits_json, '{}'), '$.title', ?)
+     WHERE id = ?`,
+    [title, id],
+  );
+}
+
 export async function deleteActivities(
   db: ReturnType<typeof useSQLiteContext>,
   ids: string[],

mobile/db/sync.ts

@@ -165,8 +165,9 @@ async function uploadLocalActivities(
     timeseries_json: string | null;
     geojson: string | null;
     original_path: string | null;
+    edits_json: string | null;
   }>(
-    `SELECT id, detail_json, timeseries_json, geojson, original_path
+    `SELECT id, detail_json, timeseries_json, geojson, original_path, edits_json
      FROM activities WHERE origin = 'local' AND synced_at IS NULL`,
   );
 
@@ -189,6 +190,10 @@ async function uploadLocalActivities(
         row.original_path !== null &&
         (await FileSystem.getInfoAsync(row.original_path)).exists;
 
+      const userTitle: string | null = row.edits_json
+        ? (JSON.parse(row.edits_json).title ?? null)
+        : null;
+
       if (useRaw) {
         const filename = row.original_path!.split('/').pop() ?? 'activity.fit';
         const base64 = await FileSystem.readAsStringAsync(row.original_path!, {
@@ -197,10 +202,11 @@ async function uploadLocalActivities(
         resp = await fetch(`${instanceUrl}/api/upload/raw`, {
           method: 'POST',
           headers,
-          body: JSON.stringify({ filename, base64 }),
+          body: JSON.stringify({ filename, base64, ...(userTitle ? { user_title: userTitle } : {}) }),
         });
       } else {
         const detail = JSON.parse(row.detail_json);
+        if (userTitle) detail.title = userTitle;
         const body: Record<string, unknown> = { activity: { id: row.id, ...detail } };
         if (row.timeseries_json) body.timeseries = JSON.parse(row.timeseries_json);
         if (row.geojson)         body.geojson    = JSON.parse(row.geojson);