fix(analyze): make FTS index creation non-fatal during analyze

When the LadybugDB FTS extension cannot be loaded (e.g. macOS 12 where
libc++ lacks std::to_chars(double), or container environments without
the native extension), `gitnexus analyze --embeddings` fails at 85%
and aborts before embedding generation can run.

This is inconsistent with the MCP server's behavior: pool-adapter.ts
already treats FTS load failure as a graceful degradation (ftsLoaded =
false, BM25 search degrades, other features continue).

Change: wrap createSearchFTSIndexes() in try/catch so that:
- FTS creation failure logs a warning instead of throwing
- Embedding generation (Phase 4) proceeds normally
- `--repair-fts` remains available for explicit FTS retry
- BM25 keyword search degrades gracefully (same as MCP read path)

Affected users: macOS 12 (Monterey), any platform where the FTS
extension binary references symbols missing from the system libc++.

gitnexus/src/core/run-analyze.ts

@@ -669,22 +669,29 @@ export async function runFullAnalysis(
 
     // ── Phase 3: FTS (85–90%) ─────────────────────────────────────────
     progress('fts', 85, 'Creating search indexes...');
-    await createSearchFTSIndexes({
-      onIndexStart: options.verbose
-        ? (table, indexName) => log(`FTS: creating ${table}.${indexName}`)
-        : undefined,
-      onIndexReady: options.verbose
-        ? (table, indexName) => log(`FTS: ready ${table}.${indexName}`)
-        : undefined,
-    });
-    const missingIndexNames = await verifySearchFTSIndexes(executeQuery);
-    if (missingIndexNames.length > 0) {
-      throw new Error(
-        `FTS verification failed - missing indexes after analyze: ${missingIndexNames.join(', ')}. ` +
-          'Check FTS extension availability, then retry `gitnexus analyze --force` for a full rebuild.',
-      );
+    try {
+      await createSearchFTSIndexes({
+        onIndexStart: options.verbose
+          ? (table, indexName) => log(`FTS: creating ${table}.${indexName}`)
+          : undefined,
+        onIndexReady: options.verbose
+          ? (table, indexName) => log(`FTS: ready ${table}.${indexName}`)
+          : undefined,
+      });
+      const missingIndexNames = await verifySearchFTSIndexes(executeQuery);
+      if (missingIndexNames.length > 0) {
+        log(
+          `⚠️ FTS verification warning - missing indexes: ${missingIndexNames.join(', ')}. ` +
+            'BM25 keyword search will be degraded. Upgrade macOS or run on a compatible platform to enable FTS.',
+        );
+      } else {
+        progress('fts', 90, 'Search indexes ready');
+      }
+    } catch (ftsErr: unknown) {
+      const ftsMsg = ftsErr instanceof Error ? ftsErr.message : String(ftsErr);
+      log(`⚠️ FTS creation skipped (non-fatal): ${ftsMsg}`);
+      progress('fts', 90, 'Search indexes skipped (FTS unavailable)');
     }
-    progress('fts', 90, 'Search indexes ready');
 
     // ── Phase 3.5: Re-insert cached embeddings ────────────────────────
     // Runs on BOTH the full-rebuild path and the incremental path: