fix: address Copilot round 4 — home-relative dir resolution + project-local detection

1. _resolve_agent_dir(): expand ~/... via Path.home() + slice instead of
   expanduser(), so tests that monkeypatch Path.home() properly isolate
   the home directory (Copilot r3312731595, r3312731729)

2. Add detect_dir field to registrar_config: Hermes declares
   detect_dir='.hermes/skills' (project-local marker). CommandRegistrar
   checks detect_dir before resolving the output dir, preventing global
   dirs like ~/.hermes/skills from causing false detection in every
   project (Copilot r3312731682)

3. test_update_failure_rolls_back: no additional changes needed — the
   _resolve_agent_dir fix makes the existing Path.home() monkeypatch
   effective, so ~/.hermes/skills is not found in the fake home and
   Hermes is properly skipped.

Tests: 2236 passed (2009 integration + 195 extension + 32 hermes)

Author: majordave

src/specify_cli/agents.py

@@ -669,7 +669,10 @@ def _resolve_agent_dir(
         """
         dir_str = agent_config["dir"]
         if dir_str.startswith("~"):
-            agent_dir = Path(dir_str).expanduser()
+            # Use Path.home() + remainder instead of expanduser() so tests
+            # that monkeypatch Path.home() can properly isolate the home dir.
+            # expanduser() uses OS env/user lookup and ignores monkeypatches.
+            agent_dir = Path.home() / dir_str[1:].lstrip("/")
         else:
             p = Path(dir_str)
             agent_dir = p if p.is_absolute() else project_root / p
@@ -714,6 +717,15 @@ def register_commands_for_all_agents(
 
         self._ensure_configs()
         for agent_name, agent_config in self.AGENT_CONFIGS.items():
+            # Check detect_dir first (project-local marker) if configured,
+            # falling back to the resolved dir for output.  This prevents
+            # global dirs (e.g. ~/.hermes/skills) from causing false
+            # detection in every project.
+            detect_dir_str = agent_config.get("detect_dir")
+            if detect_dir_str:
+                detect_path = project_root / detect_dir_str
+                if not detect_path.exists():
+                    continue
             agent_dir = self._resolve_agent_dir(
                 agent_name, agent_config, project_root,
             )
@@ -765,6 +777,11 @@ def register_commands_for_non_skill_agents(
         for agent_name, agent_config in self.AGENT_CONFIGS.items():
             if agent_config.get("extension") == "/SKILL.md":
                 continue
+            detect_dir_str = agent_config.get("detect_dir")
+            if detect_dir_str:
+                detect_path = project_root / detect_dir_str
+                if not detect_path.exists():
+                    continue
             agent_dir = self._resolve_agent_dir(
                 agent_name, agent_config, project_root,
             )

src/specify_cli/integrations/hermes/__init__.py

@@ -45,6 +45,7 @@ class HermesIntegration(SkillsIntegration):
     }
     registrar_config = {
         "dir": "~/.hermes/skills",
+        "detect_dir": ".hermes/skills",
         "format": "markdown",
         "args": "$ARGUMENTS",
         "extension": "/SKILL.md",