feat: LLM intent router, direct chat execution, and Memory V2 light intervention

Wire chat intent routing with direct_chat on regular sessions, skill-selected
short-circuit to Agent, memory light/heavy intervention tiers, and fix direct
chat UI stuck streaming after completion.

Co-authored-by: Cursor <cursoragent@cursor.com>

memory-v2-runtime.mjs

@@ -7,6 +7,7 @@ import { createMemoryV2PluginBackends } from './memory-v2-plugin-backends.mjs';
 import { createMem0HttpClient, createMem0MemoryBackend } from './memory-v2-mem0.mjs';
 import { createNeo4jHttpClient, createNeo4jMemoryBackend } from './memory-v2-neo4j.mjs';
 import { createPgvectorMemoryBackend } from './memory-v2-pgvector.mjs';
+import { backfillLegacyMemoriesToPgvector } from './memory-v2-pgvector-backfill.mjs';
 import { createQdrantHttpClient, createQdrantMemoryBackend } from './memory-v2-qdrant.mjs';
 import { createRedisStreamsClient, createRedisStreamsMemoryBackend } from './memory-v2-redis-streams.mjs';
 import { createWeaviateHttpClient, createWeaviateMemoryBackend } from './memory-v2-weaviate.mjs';
@@ -55,6 +56,7 @@ async function createPgPool(connectionString, { importPg, max }) {
 
 export async function createMemoryV2Runtime({
   legacyMemoryService = null,
+  mysqlPool = null,
   env = process.env,
   logger = console,
   importPg = (specifier) => import(specifier),
@@ -75,6 +77,8 @@ export async function createMemoryV2Runtime({
   const closers = [];
 
   let pgvectorBackend = null;
+  let pgPoolRef = null;
+  let pgEmbedQuery = null;
   if (pgvectorEnabled && connectionString) {
     try {
       const embedQuery = await loadEmbeddingModule(embeddingModule, importModule);
@@ -90,6 +94,8 @@ export async function createMemoryV2Runtime({
           max: Math.max(1, Number(env?.MEMORY_PGVECTOR_POOL_MAX ?? 5) || 5),
         });
         closers.push(() => pool.end?.());
+        pgPoolRef = pool;
+        pgEmbedQuery = embedQuery;
         pgvectorBackend = createPgvectorMemoryBackend({
           pool,
           enabled: pgvectorEnabled,
@@ -401,6 +407,55 @@ export async function createMemoryV2Runtime({
     logger,
   });
 
+  const pgBackfillEnabled = readFlag(env, 'MEMORY_PGVECTOR_BACKFILL_ENABLED', pgvectorEnabled);
+  let pgBackfillBusy = false;
+  let pgBackfillCursor = { updatedAt: 0, id: '' };
+
+  async function syncPgvectorFromLegacy() {
+    if (!pgBackfillEnabled || !pgPoolRef || !pgEmbedQuery || !mysqlPool?.query) return;
+    if (pgBackfillBusy) return;
+    pgBackfillBusy = true;
+    try {
+      const maxBatches = Math.max(1, Number(env?.MEMORY_PGVECTOR_BACKFILL_MAX_BATCHES ?? 3) || 3);
+      const batchLimit = Math.max(1, Number(env?.MEMORY_PGVECTOR_BACKFILL_LIMIT ?? 50) || 50);
+      for (let batch = 0; batch < maxBatches; batch += 1) {
+        const result = await backfillLegacyMemoriesToPgvector({
+          mysqlPool,
+          pgPool: pgPoolRef,
+          embedMemory: (item) => pgEmbedQuery(item.text, item),
+          tableName: env?.MEMORY_PGVECTOR_TABLE,
+          cursor: pgBackfillCursor,
+          limit: batchLimit,
+          dryRun: false,
+        });
+        pgBackfillCursor = result.nextCursor;
+        if (!result.hasMore || result.scanned === 0) break;
+      }
+    } catch (err) {
+      logger?.warn?.(
+        `[memory-v2] pgvector backfill skipped: ${err instanceof Error ? err.message : err}`,
+      );
+    } finally {
+      pgBackfillBusy = false;
+    }
+  }
+
+  function wrapMemorySideEffect(methodName) {
+    const original = memory[methodName].bind(memory);
+    memory[methodName] = async (input = {}) => {
+      const result = await original(input);
+      if ((result?.memories ?? 0) > 0 || (result?.analyzed ?? 0) > 0) {
+        void syncPgvectorFromLegacy();
+      }
+      return result;
+    };
+  }
+
+  if (pgBackfillEnabled && pgPoolRef && pgEmbedQuery && mysqlPool) {
+    wrapMemorySideEffect('write');
+    wrapMemorySideEffect('compact');
+  }
+
   memory.close = async () => {
     const results = await Promise.allSettled(closers.map((close) => close()));
     for (const result of results) {
@@ -417,6 +472,7 @@ export async function createMemoryV2Runtime({
 
 export async function createManagedMemoryV2Runtime({
   legacyMemoryService = null,
+  mysqlPool = null,
   configService = null,
   env = process.env,
   logger = console,
@@ -478,6 +534,7 @@ export async function createManagedMemoryV2Runtime({
     }
     const nextRuntime = await createMemoryV2Runtime({
       legacyMemoryService,
+      mysqlPool,
       env: state.effectiveEnv,
       logger,
       importPg,