feat: implemented the v1 browser embedded LLM support (Gemma 4 E4B based)

src/core/config-upgrader/KGConfigUpgrader.ts

@@ -1,6 +1,7 @@
 import { KGConfigStorage } from '../io/KGConfigStorage';
 import { CONFIG_UPGRADER_CONSTANTS } from '../../constants/coreConstants';
 import { upgradeConfigToV1 } from './upgradeConfigToV1';
+import { upgradeConfigToV2 } from './upgradeConfigToV2';
 
 /**
  * KGConfigUpgrader — Orchestrates app-level migrations (e.g., storage backend changes).
@@ -33,6 +34,10 @@ export class KGConfigUpgrader {
           await upgradeConfigToV1();
           break;
         }
+        case 2: {
+          await upgradeConfigToV2();
+          break;
+        }
         default: {
           throw new Error(`No config upgrader found for version ${nextVersion}`);
         }

src/core/config-upgrader/upgradeConfigToV2.test.ts

@@ -0,0 +1,54 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const configStore = new Map<string, { name: string; data: Record<string, unknown>; lastModified: number }>();
+
+vi.mock('../io/KGConfigStorage', () => ({
+  KGConfigStorage: {
+    getInstance: () => ({
+      getRaw: vi.fn(async (name: string) => configStore.get(name)?.data ?? null),
+      saveRaw: vi.fn(async (name: string, data: Record<string, unknown>) => {
+        configStore.set(name, { name, data, lastModified: Date.now() });
+      }),
+    }),
+  },
+}));
+
+import { upgradeConfigToV2 } from './upgradeConfigToV2';
+
+describe('upgradeConfigToV2', () => {
+  beforeEach(() => {
+    configStore.clear();
+  });
+
+  it('pins legacy installs without an explicit provider to the old default provider', async () => {
+    configStore.set('userConfig', {
+      name: 'userConfig',
+      data: {
+        general: {
+          openai: { api_key: '', model: 'gpt-5.4-mini', flex: false },
+        },
+      },
+      lastModified: Date.now(),
+    });
+
+    await upgradeConfigToV2();
+
+    expect((configStore.get('userConfig')?.data.general as Record<string, unknown>).llm_provider).toBe('openai');
+  });
+
+  it('leaves explicit providers unchanged', async () => {
+    configStore.set('userConfig', {
+      name: 'userConfig',
+      data: {
+        general: {
+          llm_provider: 'openai_compatible',
+        },
+      },
+      lastModified: Date.now(),
+    });
+
+    await upgradeConfigToV2();
+
+    expect((configStore.get('userConfig')?.data.general as Record<string, unknown>).llm_provider).toBe('openai_compatible');
+  });
+});

src/core/config-upgrader/upgradeConfigToV2.ts

@@ -0,0 +1,25 @@
+import { KGConfigStorage } from '../io/KGConfigStorage';
+
+const CONFIG_KEY = 'userConfig';
+const LEGACY_DEFAULT_PROVIDER = 'openai';
+
+export async function upgradeConfigToV2(): Promise<void> {
+  const storage = KGConfigStorage.getInstance();
+  const rawConfig = await storage.getRaw(CONFIG_KEY);
+  if (!rawConfig || typeof rawConfig !== 'object') {
+    return;
+  }
+
+  const config = rawConfig as Record<string, unknown>;
+  const general = config.general;
+  if (!general || typeof general !== 'object') {
+    return;
+  }
+
+  if ('llm_provider' in (general as Record<string, unknown>)) {
+    return;
+  }
+
+  (general as Record<string, unknown>).llm_provider = LEGACY_DEFAULT_PROVIDER;
+  await storage.saveRaw(CONFIG_KEY, config);
+}

src/core/config/ConfigManager.ts

@@ -6,7 +6,7 @@ import { KGConfigStorage } from '../io/KGConfigStorage';
 interface AppConfig {
   general: {
     language: string;
-    llm_provider: 'openai' | 'gemini' | 'claude' | 'claude_openrouter' | 'openai_compatible';
+    llm_provider: 'local_browser' | 'openai' | 'gemini' | 'claude' | 'claude_openrouter' | 'openai_compatible';
     persist_api_keys_non_localhost: boolean;
     openai: {
       api_key: string;
@@ -183,7 +183,7 @@ export class ConfigManager {
       this.defaultConfig = {
         general: {
           language: 'en_us',
-          llm_provider: 'openai',
+          llm_provider: 'local_browser',
           persist_api_keys_non_localhost: false,
           openai: {
             api_key: '',

src/core/io/LocalSeparatorModelCache.test.ts

@@ -9,10 +9,12 @@ class MockWritableFileStream {
     this.handle = handle;
   }
 
-  async write(content: ArrayBuffer | ArrayBufferView): Promise<void> {
-    const bytes = content instanceof ArrayBuffer
-      ? new Uint8Array(content)
-      : new Uint8Array(content.buffer, content.byteOffset, content.byteLength);
+  async write(content: ArrayBuffer | ArrayBufferView | string): Promise<void> {
+    const bytes = typeof content === 'string'
+      ? new TextEncoder().encode(content)
+      : content instanceof ArrayBuffer
+        ? new Uint8Array(content)
+        : new Uint8Array(content.buffer, content.byteOffset, content.byteLength);
     this.chunks.push(new Uint8Array(bytes));
   }
 
@@ -44,6 +46,8 @@ class MockFileSystemFileHandle {
 
   async getFile(): Promise<File> {
     return {
+      size: this.content.byteLength,
+      text: async () => new TextDecoder().decode(this.content),
       arrayBuffer: async () => this.content.buffer.slice(0),
     } as unknown as File;
   }