fix(mcp): eliminate "No such tool available" race at agent wakeup

When Paperclip wakes the CEO and the model issues an mcp__legal-ai__*
call within ~10s of session init, Claude Code sometimes returns
"No such tool available" because the legal-ai MCP server hasn't
finished bringing up its tool catalog yet. Observed twice today on
CMPA precedent-extraction wakeups (sessions 9989fbaf and a9c61801);
the agent fell back to bash + .venv/bin/python and finished the work,
but the race needed fixing on the server side.

Three changes that close the window:

1. Lazy schema init (services/db.py + server.py)
   `init_schema()` was awaited inside the FastMCP lifespan, blocking
   the `initialize`/`tools/list` handshake until ~10 CREATE TABLE IF
   NOT EXISTS statements ran. Under contention (two CEOs waking at
   once for different companies) this stretched. Now the lifespan
   returns immediately and `get_pool()` runs the schema migrations
   exactly once on first DB access, guarded by an asyncio.Lock.
   tools/list is answered in milliseconds regardless of DB state.

2. Lazy heavy imports
   - services/embeddings.py: voyageai (~450ms) loaded only inside
     _get_client()
   - services/extractor.py: google.cloud.vision (~550ms) loaded only
     inside _get_vision_client() and _ocr_with_google_vision()
   These two were being imported at module top from
   legal_mcp.tools.documents -> services.processor -> services.{
   extractor,embeddings}, so the FastMCP server couldn't even start
   responding until both finished. Cold start dropped from 2.7s to
   1.17s end-to-end (init + tools/list response).

3. Agent-side warmup + retry guidance (.claude/agents/legal-ceo.md)
   Even with a fast server, the model can still race on the very
   first call. The precedent-extraction section now tells the CEO
   to call workflow_status as a warmup probe and to retry after a
   short sleep if it sees "No such tool available", before falling
   back to the python bypass.

Also expanded the precedent-tool whitelists on the sub-agents that
delegate halacha/library work (commits 4a9a6b7 + 7ee90dc added the
tools to the MCP server but only the CEO got them in its allowed
list). Added to: legal-researcher (full extraction set), legal-analyst
(library_get/list + halacha review), legal-writer (library lookups +
halacha_review), legal-qa (library_get + halacha_review), and the two
that the CEO was already missing (halacha_review, halachot_pending).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

mcp-server/src/legal_mcp/services/db.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import json
 import logging
 from datetime import date
@@ -15,23 +16,42 @@ from legal_mcp import config
 logger = logging.getLogger(__name__)
 
 _pool: asyncpg.Pool | None = None
+_schema_ready: bool = False
+_init_lock: asyncio.Lock = asyncio.Lock()
 
 
 async def get_pool() -> asyncpg.Pool:
-    global _pool
-    if _pool is None:
-        # First, ensure pgvector extension exists (before registering type codec)
-        conn = await asyncpg.connect(config.POSTGRES_URL)
-        await conn.execute('CREATE EXTENSION IF NOT EXISTS vector')
-        await conn.execute('CREATE EXTENSION IF NOT EXISTS "uuid-ossp"')
-        await conn.close()
+    """Return the connection pool, creating it (and running schema init) lazily.
+
+    The MCP server's `lifespan` no longer blocks on schema init — it's done
+    here on first DB access. This keeps the `initialize`/`tools/list` MCP
+    handshake immediate so Claude Code never sees a stale "No such tool".
+    """
+    global _pool, _schema_ready
+    if _pool is not None and _schema_ready:
+        return _pool
+
+    async with _init_lock:
+        if _pool is None:
+            # First, ensure pgvector extension exists (before registering type codec)
+            conn = await asyncpg.connect(config.POSTGRES_URL)
+            try:
+                await conn.execute('CREATE EXTENSION IF NOT EXISTS vector')
+                await conn.execute('CREATE EXTENSION IF NOT EXISTS "uuid-ossp"')
+            finally:
+                await conn.close()
+
+            _pool = await asyncpg.create_pool(
+                config.POSTGRES_URL,
+                min_size=2,
+                max_size=10,
+                init=_init_connection,
+            )
+
+        if not _schema_ready:
+            await _run_schema_migrations(_pool)
+            _schema_ready = True
 
-        _pool = await asyncpg.create_pool(
-            config.POSTGRES_URL,
-            min_size=2,
-            max_size=10,
-            init=_init_connection,
-        )
     return _pool
 
 
@@ -671,8 +691,7 @@ CREATE INDEX IF NOT EXISTS idx_prec_img_emb_case_law
 """
 
 
-async def init_schema() -> None:
-    pool = await get_pool()
+async def _run_schema_migrations(pool: asyncpg.Pool) -> None:
     async with pool.acquire() as conn:
         await conn.execute(SCHEMA_SQL)
         await conn.execute(MIGRATIONS_SQL)
@@ -687,6 +706,11 @@ async def init_schema() -> None:
     logger.info("Database schema initialized (v1-v9)")
 
 
+async def init_schema() -> None:
+    """Backward-compatible wrapper. Schema init now runs lazily inside get_pool()."""
+    await get_pool()
+
+
 # ── Case CRUD ───────────────────────────────────────────────────────
 
 async def create_case(