replace Redis with an embedded SQLite string->string KV store (group commit, in-tx events, SQL search)

dashboard/src/pages/Dashboard.tsx

@@ -215,9 +215,9 @@ export default function Dashboard() {
           }
         />
         <Tile
-          label="Redis keys"
+          label="Store keys"
           value={formatCount(stats?.redisKeys)}
-          note={stats?.redisMemory ? `${stats.redisMemory} in use` : undefined}
+          note={stats?.redisMemory ? `${stats.redisMemory} on disk` : undefined}
         />
         <Tile
           label="Identities"
@@ -239,7 +239,7 @@ export default function Dashboard() {
                 {health.status === 'ok' ? 'Healthy' : health.status}
               </div>
               <p style={noteStyle}>
-                Redis: {health.redis ? 'Connected' : 'Disconnected'}
+                Metadata store: {health.redis ? 'Open' : 'Unavailable'}
               </p>
             </>
           ) : (

dashboard/src/pages/Identity.tsx

@@ -179,7 +179,7 @@ async function fetchAccounts(): Promise<Account[]> {
 // Resolve an account's display name from the User Data Layer, or null.
 //
 // Never throws and never reports an error upward: a name is decoration on top
-// of the uid, and the account list must render identically whether Redis is up
+// of the uid, and the account list must render identically whether the store is up
 // (identity itself is file-backed, the UDL is not). The name is also *unsigned*
 // — meta-core stores the plaintext beside the signed record and verifies
 // nothing — so the uid stays on screen as the real identity, and the length cap
@@ -209,7 +209,7 @@ async function fetchDisplayName(uid: string): Promise<string | null> {
 // so per-row calls would walk the keyspace once per account.
 //
 // Never throws, for the same reason fetchDisplayName does not: the counts are
-// context on top of the uid, and the list must render identically when Redis is
+// context on top of the uid, and the list must render identically when the store is
 // down — accounts are file-backed, their data is not.
 //
 // Returns null on failure rather than an empty map. The difference is
@@ -603,7 +603,7 @@ function AccountCard({
                       records === 1 ? 'record' : 'records'
                     } — likes, ratings, watch progress across ${titles.toLocaleString()} ${
                       titles === 1 ? 'title' : 'titles'
-                    } — are permanently deleted from Redis, along with every index that names this uid.`}{' '}
+                    } — are permanently deleted from the metadata store, along with every index that names this uid.`}{' '}
               This cannot be undone and there is no backup.
             </li>
             <li>
@@ -655,12 +655,12 @@ export default function Identity() {
       return;
     }
     if (gen !== reqGen.current) return;
-    // Render the list before resolving names, so a down Redis delays nothing.
+    // Render the list before resolving names, so a down store delays nothing.
     setAccounts(list);
     setLoading(false);
 
     // Names and counts both come after the list is on screen, and neither can
-    // fail the page: a down Redis costs decoration, not the account list.
+    // fail the page: a down store costs decoration, not the account list.
     const [settled, counts] = await Promise.all([
       Promise.allSettled(list.map((a) => fetchDisplayName(a.uid))),
       fetchStats(),