feat(a4,c3b): complete A-4 Phase 2 agent knowledge migration & Option B isolation removal

- Option B / C-3b: Deprecate isolation.root and remove its 4 legacy consumers in lib.sh, workspace_uuid.py, verify_session.py, and stop_session.sh.
- M2~M7 Migration: Implement artifact_path, verify_artifact, purge_artifacts, spawn_spec, resume_spec, auth_ok, discover, ready_tokens, exit_key, and delegate_agent_key across BaseAgentAdapter and all 4 adapters (Claude, Agy, Hermes, Cline).
- Migrate shell duplications in lib.sh, create_session.sh, resume_session.sh, stop_session.sh, and reconcile.sh to python -m lib_py.agents facts.
- Hardening & Corrections: Fix Cline resume_spec flag to '-i --id', apply shlex.quote across all facts variables with MAM_ prefix, add safe fallback in wait_for_tui_ready.
- Add comprehensive contract tests in tests/test_a4_adapter_contract.py and sync IMPROVEMENTS.md / LOG.md.
- Verified: 100% PASS across unit, component, contract, and integration tests.

.agents/skills/lib_py/agents/base.py

@@ -13,10 +13,24 @@ class SpawnSpec:
         self.env = env or {}
 
 class DiscoveryContext:
-    def __init__(self, workspace: str, agent_name: str, home_dir: Optional[str] = None):
+    def __init__(self, workspace: str, agent_name: str = "", home_dir: Optional[str] = None,
+                 claude_dir: Optional[str] = None, epoch: int = 0,
+                 row: Optional[Dict[str, Any]] = None, mode: str = "discover"):
         self.workspace = workspace
         self.agent_name = agent_name
         self.home_dir = resolve_home(home_dir)
+        self.claude_dir = claude_dir or os.environ.get("CLAUDE_PROJECT_DIR", f"{self.home_dir}/.claude/projects")
+        self.epoch = epoch
+        self.row = row or {}
+        self.mode = mode
+
+    @property
+    def ws_key(self) -> str:
+        return workspace_key(self.workspace)
+
+    @property
+    def cwd(self) -> str:
+        return (self.row.get("pane", {}).get("cwd", "") if isinstance(self.row, dict) else "") or self.workspace
 
 class BaseAgentAdapter:
     @property
@@ -27,6 +41,22 @@ class BaseAgentAdapter:
     def own_key(self) -> str:
         raise NotImplementedError
 
+    @property
+    def ready_tokens(self) -> str:
+        raise NotImplementedError
+
+    @property
+    def exit_key(self) -> str:
+        raise NotImplementedError
+
+    @property
+    def delegate_agent_key(self) -> str:
+        raise NotImplementedError
+
+    @property
+    def identity_cache_fields(self) -> tuple:
+        raise NotImplementedError
+
     @property
     def input_prompt(self) -> Optional[str]:
         return None
@@ -51,3 +81,24 @@ class BaseAgentAdapter:
 
     def verify_session(self, ws: str, uuid: str, row: Optional[Dict[str, Any]] = None, mode: str = "discover") -> bool:
         return verify_session_uuid(ws, self.name, uuid, row=row, mode=mode)
+
+    def artifact_path(self, uuid: str, ctx: DiscoveryContext) -> str:
+        raise NotImplementedError
+
+    def verify_artifact(self, uuid: str, ctx: DiscoveryContext) -> bool:
+        raise NotImplementedError
+
+    def purge_artifacts(self, uuid: str, ctx: DiscoveryContext) -> list:
+        raise NotImplementedError
+
+    def spawn_spec(self, binary: str, session_uuid: str = "", use_wrapper: bool = False) -> str:
+        raise NotImplementedError
+
+    def resume_spec(self, binary: str, session_uuid: str, materialized: bool = False) -> str:
+        raise NotImplementedError
+
+    def auth_ok(self, run_cmd: Optional[Any] = None) -> bool:
+        raise NotImplementedError
+
+    def discover(self, ctx: DiscoveryContext) -> list:
+        raise NotImplementedError