feat(stats): add headword sentence search and rename related words

- Search by headword enabled by default; finds inflected variants (e.g. 知らない → 知らねえ)
- Add "Search by headword" toggle to switch back to exact text/title matching
- Rename "Similar Words" → "Related Seen Words" with tighter matching (same reading/shared kanji)
- ankiConnect.deck falls back to Yomitan mining deck when empty

src/main/runtime/config-settings-runtime.test.ts

@@ -1,6 +1,10 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
 import { DEFAULT_CONFIG, deepCloneConfig } from '../../config';
+import { resolveConfig } from '../../config/resolve';
 import { IPC_CHANNELS } from '../../shared/ipc/contracts';
 import { createConfigSettingsRuntime } from './config-settings-runtime';
 
@@ -10,7 +14,13 @@ test('config settings runtime exposes inferred Yomitan Anki deck lookup', async
     fields: [],
     getConfigPath: () => '/tmp/config.jsonc',
     getRawConfig: () => ({}),
-    getConfig: () => deepCloneConfig(DEFAULT_CONFIG),
+    getConfig: () => ({
+      ...deepCloneConfig(DEFAULT_CONFIG),
+      ankiConnect: {
+        ...deepCloneConfig(DEFAULT_CONFIG).ankiConnect,
+        deck: 'Configured',
+      },
+    }),
     getWarnings: () => [],
     reloadConfigStrict: () =>
       ({
@@ -48,3 +58,62 @@ test('config settings runtime exposes inferred Yomitan Anki deck lookup', async
   assert.ok(handler);
   assert.deepEqual(await handler({}, undefined), { ok: true, value: 'Mining' });
 });
+
+test('config settings runtime persists inferred Yomitan Anki deck when config deck is empty', async () => {
+  const handlers = new Map<string, (event: unknown, ...args: unknown[]) => unknown>();
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-settings-'));
+  const configPath = path.join(dir, 'config.jsonc');
+  fs.writeFileSync(configPath, '{"ankiConnect":{"deck":""}}\n', 'utf-8');
+
+  try {
+    let rawConfig = { ankiConnect: { deck: '' } };
+    let resolvedConfig = resolveConfig(rawConfig).resolved;
+    const runtime = createConfigSettingsRuntime({
+      fields: [],
+      getConfigPath: () => configPath,
+      getRawConfig: () => rawConfig,
+      getConfig: () => resolvedConfig,
+      getWarnings: () => [],
+      reloadConfigStrict: () => {
+        rawConfig = JSON.parse(fs.readFileSync(configPath, 'utf-8'));
+        resolvedConfig = resolveConfig(rawConfig).resolved;
+        return {
+          ok: true,
+          config: resolvedConfig,
+          warnings: [],
+          path: configPath,
+        };
+      },
+      getSettingsWindow: () => null,
+      setSettingsWindow: () => undefined,
+      createSettingsWindow: () => ({}) as never,
+      settingsHtmlPath: '/tmp/settings.html',
+      openPath: async () => '',
+      defaultAnkiConnectUrl: DEFAULT_CONFIG.ankiConnect.url,
+      createAnkiClient: () =>
+        ({
+          deckNames: async () => [],
+          fieldNamesForDeck: async () => [],
+          modelNamesForDeck: async () => [],
+          modelNames: async () => [],
+          modelFieldNames: async () => [],
+        }) as never,
+      getYomitanAnkiDeckName: async () => 'Minecraft',
+      ipcMain: {
+        handle: (channel, listener) => {
+          handlers.set(channel, listener);
+        },
+      },
+      ipcChannels: IPC_CHANNELS.request,
+    });
+
+    runtime.registerHandlers();
+
+    const handler = handlers.get(IPC_CHANNELS.request.getConfigSettingsYomitanAnkiDeckName);
+    assert.ok(handler);
+    assert.deepEqual(await handler({}, undefined), { ok: true, value: 'Minecraft' });
+    assert.equal(JSON.parse(fs.readFileSync(configPath, 'utf-8')).ankiConnect.deck, 'Minecraft');
+  } finally {
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});