fix: instant search via frontend library cache — no Go calls at all

The HTTP endpoint approach still crashed due to Wails asset server
issues. Replaced with a pure frontend solution: searchLibraryCache()
does a substring match against the libraryStore's cached artists and
albums arrays. This is pure JS — zero Go calls, zero RPC, zero
network — guaranteed instant.

Results appear immediately as the user types. The full MB+LB search
pipeline still runs via Wails RPC and replaces the library matches
with richer results when done.

Added cachedArtists/cachedAlbums getters to LibraryStore for
synchronous read-only access to the already-loaded data.
Removed the /api/search-local HTTP handler from the backend.

backend/app.go

@@ -118,9 +118,6 @@ func NewYellowJacketApp(
 		yjApp.assetHandler.RegisterHandler("/artist-images/", artistImgHandler)
 	}
 
-	// Register local search endpoint — bypasses Wails RPC serialization.
-	yjApp.assetHandler.RegisterHandler("/api/search-local", yjApp.explore.SearchLocalHandler())
-
 	// create playlist service
 	yjApp.playlist = playlist.NewService(
 		yjApp.logger, yjApp.database, yjApp.appConfig,

backend/explore/explore.go

@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"log/slog"
 	"math"
-	"net/http"
 	"sort"
 	"strings"
 	"sync"
@@ -155,38 +154,6 @@ func (e *Service) SearchLocal(query string) *MBSearchResult {
 	return &result
 }
 
-// SearchLocalHandler returns an http.Handler that serves local
-// index search results as JSON.  This bypasses the Wails RPC
-// serialization queue, ensuring sub-millisecond response times.
-func (e *Service) SearchLocalHandler() http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		defer func() {
-			if rv := recover(); rv != nil {
-				e.logger.Error("search-local handler panic", "recover", rv)
-				http.Error(w, "internal error", http.StatusInternalServerError)
-			}
-		}()
-
-		query := r.URL.Query().Get("q")
-		if query == "" {
-			w.Header().Set("Content-Type", "application/json")
-			_, _ = w.Write([]byte("null"))
-			return
-		}
-
-		result := e.SearchLocal(query)
-
-		w.Header().Set("Content-Type", "application/json")
-
-		if result == nil {
-			_, _ = w.Write([]byte("null"))
-			return
-		}
-
-		_ = json.NewEncoder(w).Encode(result)
-	})
-}
-
 // ---------------------------------------------------------------------------
 // MusicBrainz lookup
 // ---------------------------------------------------------------------------

frontend/src/components/explore-view/explore-view.ts

@@ -9,6 +9,7 @@ import type {
     MBReleaseGroup,
     MBRecording,
 } from '@go/explore/Service';
+import { libraryStore } from '../../store/library-store';
 import '@awesome.me/webawesome/dist/components/icon/icon.js';
 
 /* ── Constants ── */
@@ -520,35 +521,74 @@ export class ExploreView extends LitElement {
         const startTime = performance.now();
         console.log(`[explore] search started: "${query}"`);
 
-        // Phase 1: fetch local index results via HTTP (bypasses Wails
-        // RPC serialization — guaranteed instant).
-        try {
-            const resp = await fetch(`/api/search-local?q=${encodeURIComponent(query)}`);
-            if (version !== this.searchVersion) return;
-            if (resp.ok) {
-                const local = await resp.json() as MBSearchResult | null;
-                if (local && (local.artists?.length || local.releaseGroups?.length || local.recordings?.length)) {
-                    this.results = local;
-                    this.loadThumbnails();
-                    this.loadArtistImages();
-                    this.checkLibrary();
-                    const elapsed = (performance.now() - startTime).toFixed(0);
-                    console.log(
-                        `[explore] local results: "${query}" in ${elapsed}ms — ` +
-                            `artists=${local.artists?.length ?? 0}, ` +
-                            `albums=${local.releaseGroups?.length ?? 0}, ` +
-                            `tracks=${local.recordings?.length ?? 0}`,
-                    );
-                }
-            }
-        } catch {
-            // Local search failed — continue to full search.
+        // Phase 1: instant library search — pure frontend, no Go calls.
+        const localResults = this.searchLibraryCache(query);
+        if (localResults && (localResults.artists?.length || localResults.releaseGroups?.length)) {
+            this.results = localResults;
+            this.loadThumbnails();
+            this.loadArtistImages();
+            const elapsed = (performance.now() - startTime).toFixed(0);
+            console.log(
+                `[explore] library results: "${query}" in ${elapsed}ms — ` +
+                    `artists=${localResults.artists?.length ?? 0}, ` +
+                    `albums=${localResults.releaseGroups?.length ?? 0}`,
+            );
         }
 
         // Phase 2: full pipeline (MB + LB + reranking) via Wails RPC.
         void this.executeFullSearch(version, query, startTime);
     }
 
+    /**
+     * Search the frontend library cache for matching artists and albums.
+     * Pure JS — no Go calls, guaranteed instant.
+     */
+    private searchLibraryCache(query: string): MBSearchResult | null {
+        const q = query.toLowerCase();
+
+        const artists: MBArtist[] = [];
+        const cachedArtists = libraryStore.cachedArtists;
+        if (cachedArtists) {
+            for (const a of cachedArtists) {
+                if (a.Name.toLowerCase().includes(q)) {
+                    artists.push({
+                        mbid: '',
+                        name: a.Name,
+                        sortName: '',
+                        type: 'Group',
+                        country: '',
+                        disambiguation: '',
+                        score: 100,
+                    } as MBArtist);
+                    if (artists.length >= 5) break;
+                }
+            }
+        }
+
+        const releaseGroups: MBReleaseGroup[] = [];
+        const cachedAlbums = libraryStore.cachedAlbums;
+        if (cachedAlbums) {
+            for (const a of cachedAlbums) {
+                if (a.Name.toLowerCase().includes(q) || a.ArtistName.toLowerCase().includes(q)) {
+                    releaseGroups.push({
+                        mbid: '',
+                        title: a.Name,
+                        primaryType: 'Album',
+                        artistCredit: a.ArtistName,
+                        firstReleaseDate: a.Year ? String(a.Year) : '',
+                    } as MBReleaseGroup);
+                    if (releaseGroups.length >= 5) break;
+                }
+            }
+        }
+
+        if (artists.length === 0 && releaseGroups.length === 0) {
+            return null;
+        }
+
+        return { artists, releaseGroups, recordings: [] } as MBSearchResult;
+    }
+
     private async executeFullSearch(version: number, query: string, startTime: number) {
         try {
             const result = await Search(query);

frontend/src/store/library-store.ts

@@ -120,6 +120,16 @@ class LibraryStore {
     // Returns cached data or fetches from backend on first access.
     // ===================================================================
 
+    /** Synchronous access to cached artists (null if not yet loaded). */
+    get cachedArtists(): library.Artist[] | null {
+        return this.artists;
+    }
+
+    /** Synchronous access to cached albums (null if not yet loaded). */
+    get cachedAlbums(): library.Album[] | null {
+        return this.albums;
+    }
+
     async getTracks(): Promise<library.Track[]> {
         if (this.tracks !== null) {
             return this.tracks;