feat: add pty monitoring

src/claude_code_api/backend.py

@@ -149,6 +149,18 @@ class ClaudeCodeBackend:
     def live_session_count(self) -> int:
         return len(self._sessions)
 
+    @property
+    def live_sessions(self) -> dict[str, PtyClaudeProcess]:
+        """Snapshot of live PTY processes keyed by ``session_id``.
+
+        Returned dict is a copy — caller may iterate freely without
+        worrying about concurrent ``complete()`` calls reshuffling
+        ``_sessions`` (which is keyed by history fingerprint, not
+        ``session_id``). Intended for debug surfaces (e.g. admin
+        terminal viewer) that need to look up a session by id.
+        """
+        return {s.session_id: s.pty for s in self._sessions.values()}
+
     async def complete(self, messages: list[Mapping[str, Any]]) -> AsyncIterator[Event]:
         """Run one turn against the matching session (or spawn one).