fix(stall_watch): call herdr with the sanitized agent name (Issue #66)

herdr registers an agent under sanitize_herdr_agent_name(session), so a
session name over 32 characters or with upper-case letters got
agent_not_found and stall detection went off. stall_watch now converts the
name for every herdr call (agent get/read/prompt, watcher.wait_once); logs
and notices keep the original name, and the agent kind is still read off
the original suffix (a long name's sanitized form ends in a hash).

The conftest mock herdr gets an opt-in strict_agent_names mode that, like
the real herdr, answers an agent only under its registered name and fails
get/read with agent_not_found JSON; existing tests see no change.

Refs #66

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/conftest.py

@@ -470,6 +470,9 @@ def _sanitize_agent_name(name):
 def _match_agent(k, target):
     if not k or not target:
         return False
+    # Issue #66: like the real herdr, answer only the registered (sanitized) name.
+    if state.get("strict_agent_names"):
+        return k == target
     return k == target or _sanitize_agent_name(k) == target or _sanitize_agent_name(target) == k or _sanitize_agent_name(k) == _sanitize_agent_name(target)
 
 args = sys.argv[1:]
@@ -1052,6 +1055,10 @@ elif cmd1 == "agent":
             }))
             sys.exit(0)
         else:
+            if state.get("strict_agent_names"):
+                sys.stderr.write(json.dumps({"error": {"code": "agent_not_found",
+                                                       "message": "agent " + name + " not found"}}) + "\\n")
+                sys.exit(1)
             sys.stderr.write("Agent " + name + " not found\\n")
             sys.exit(1)
     elif cmd2 == "wait":
@@ -1143,6 +1150,10 @@ elif cmd1 == "agent":
             print(buffer_content)
             sys.exit(0)
         else:
+            if state.get("strict_agent_names"):
+                sys.stderr.write(json.dumps({"error": {"code": "agent_not_found",
+                                                       "message": "agent " + name + " not found"}}) + "\\n")
+                sys.exit(1)
             sys.stderr.write("Agent " + name + " not found\\n")
             sys.exit(1)
     elif cmd2 == "prompt":