fix(security): persistent search index forgets redacted and left-room text

Nothing ever removed an indexed row: redacted messages stayed searchable
with full plaintext and rendered as normal results. Now: a client-level
RoomEvent.Redaction listener deletes the row, leave/ban clears the room
(clearRoom finally has a caller), m.replace edits upsert the original
row instead of indexing the "* fallback" separately, and cached rows
whose local event is redacted render through the existing
redacted_because placeholder. Unit-tested.

Fixes #14

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/features/message-search/useLocalMessageSearch.test.ts

@@ -0,0 +1,56 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { SearchCacheRow } from '../../utils/searchCache';
+
+// useLocalMessageSearch.ts imports searchCacheEnabledAtom, which touches
+// localStorage at module-load time (atomWithLocalStorage reads the initial
+// value eagerly). Stub it before a dynamic import — a static import would
+// hoist above the stub. Same pattern as state/plaintextCaches.test.ts.
+(globalThis as { localStorage?: unknown }).localStorage = {
+  getItem: () => null,
+  setItem: () => {},
+  removeItem: () => {},
+};
+
+const { rowToResultItem } = await import('./useLocalMessageSearch');
+
+const row = (overrides: Partial<SearchCacheRow> = {}): SearchCacheRow => ({
+  roomId: '!r1',
+  eventId: '$1',
+  ts: 100,
+  sender: '@a',
+  body: 'hello world',
+  ...overrides,
+});
+
+// Gitea #14 — cached rows for a locally-known-redacted event must carry a
+// `redacted_because` marker so SearchResultGroup's guard renders the
+// "message deleted" placeholder instead of the stale plaintext.
+
+test('rowToResultItem: plain row has no redacted_because marker', () => {
+  const item = rowToResultItem(row());
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  assert.equal((item.event as any).unsigned?.redacted_because, undefined);
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  assert.equal((item.event as any).content.body, 'hello world');
+});
+
+test('rowToResultItem: redacted=true sets the redacted_because marker', () => {
+  const item = rowToResultItem(row(), true);
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  assert.ok((item.event as any).unsigned?.redacted_because);
+});
+
+test('rowToResultItem: falls back to pollText when body is empty', () => {
+  const item = rowToResultItem(row({ body: '', pollText: 'question answer' }));
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  assert.equal((item.event as any).content.body, 'question answer');
+});
+
+test('rowToResultItem: carries formattedBody as HTML when present', () => {
+  const item = rowToResultItem(row({ formattedBody: '<b>hi</b>' }));
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  const content = (item.event as any).content;
+  assert.equal(content.format, 'org.matrix.custom.html');
+  assert.equal(content.formatted_body, '<b>hi</b>');
+});