fix: clear-search restores board and enable partial-match search

- useTasks debounced effect bailed when searchQuery transitioned back to
  undefined (App passes `searchQuery || undefined`), so clearing the
  input never refetched the unfiltered list. Track previous value via
  ref and only skip the initial mount.
- FTS5 search used bare tokens (exact term match), so "frob" did not
  match "frobnicator". Append `*` to each token (and to quoted tokens)
  for prefix matching. LIKE fallback already did substring matching.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/core/src/store.ts

@@ -2489,12 +2489,14 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
     if (this.db.fts5Available) {
       // For FTS5 MATCH, quote tokens that contain special characters like hyphens
       // to prevent them from being interpreted as operators
+      // Append `*` to each token for FTS5 prefix matching so partial input
+      // (e.g., "frob") matches indexed terms like "frobnicator".
       const ftsQuery = sanitizedTokens
         .map((token) => {
           if (/[":(){}*^+-]/.test(token)) {
-            return `"${token.replace(/"/g, '\\"')}"`;
+            return `"${token.replace(/"/g, '\\"')}"*`;
           }
-          return token;
+          return `${token}*`;
         })
         .join(" OR ");
       const whereClause = includeArchived ? "" : ` AND t."column" != 'archived'`;