feat: wire Sam21Client into _deps and config

Adds services.sam21 (base_url + timeout_s) and grasp.use_sam21 toggle.

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

src/presa_mano/api/_deps.py

@@ -6,7 +6,7 @@ from __future__ import annotations
 from pathlib import Path
 from typing import Any
 
-from ..clients import G1Client, MarkerClient, NuwaClient, YoloClient
+from ..clients import G1Client, MarkerClient, NuwaClient, Sam21Client, YoloClient
 from ..config import data_dir, get_config
 
 
@@ -29,6 +29,14 @@ def yolo() -> YoloClient:
     return YoloClient(c["base_url"], timeout_s=c.get("timeout_s", 10.0))
 
 
+def sam21() -> Sam21Client:
+    c = _svc(get_config(), "sam21")
+    return Sam21Client(
+        base_url=c.get("base_url", "http://localhost:8002"),
+        timeout_s=float(c.get("timeout_s", 10.0)),
+    )
+
+
 def active_robot_key() -> str:
     """Which robot the orchestrator is currently bound to ('g1' or 'h1').
     Read from `robot.active` in config; defaults to 'g1' for backward compat."""