Initial commit: Matrix Bridge Daemon

Persistent Python daemon connecting Matrix DM room to AiAgent API.

- Config-driven (JSON config file)
- Extensible command system (/new_session, /help)
- Typing indicators while agent processes
- Session auto-naming for identification
- Persistent state across restarts
- Token refresh, retry logic, error handling
- Python stdlib only — no external dependencies

state.py

@@ -0,0 +1,74 @@
+"""Persistent state management for the bridge.
+
+Saves and loads session ID, Matrix sync batch token, and processed event IDs
+so the bridge survives crashes and restarts without losing context.
+"""
+
+from __future__ import annotations
+
+import json
+import logging
+import os
+from typing import Optional
+
+log = logging.getLogger("matrix-bridge.state")
+
+
+class BridgeState:
+    """Persistent state that survives bridge restarts."""
+
+    def __init__(
+        self,
+        session_id: Optional[str] = None,
+        next_batch: Optional[str] = None,
+        processed_event_ids: Optional[list[str]] = None,
+    ):
+        self.session_id = session_id
+        self.next_batch = next_batch
+        self.processed_event_ids = processed_event_ids or []
+
+    @classmethod
+    def load(cls, path: str) -> "BridgeState":
+        """Load state from disk, or return defaults."""
+        if os.path.exists(path):
+            try:
+                with open(path, "r") as f:
+                    data = json.load(f)
+                return cls(
+                    session_id=data.get("session_id"),
+                    next_batch=data.get("next_batch"),
+                    processed_event_ids=data.get("processed_event_ids", []),
+                )
+            except (json.JSONDecodeError, IOError) as e:
+                log.warning(f"Failed to load state file: {e}")
+        return cls()
+
+    def save(self, path: str) -> None:
+        """Persist state to disk."""
+        data = {
+            "session_id": self.session_id,
+            "next_batch": self.next_batch,
+            "processed_event_ids": self.processed_event_ids,
+        }
+        try:
+            with open(path, "w") as f:
+                json.dump(data, f, indent=2)
+        except IOError as e:
+            log.error(f"Failed to save state: {e}")
+
+    def mark_processed(self, event_ids: list[str], limit: int = 200) -> None:
+        """Add event IDs to the processed set and trim to prevent bloat."""
+        processed = set(self.processed_event_ids)
+        for eid in event_ids:
+            processed.add(eid)
+        if len(processed) > limit:
+            processed = set(list(processed)[-limit:])
+        self.processed_event_ids = list(processed)
+
+    def __repr__(self) -> str:
+        return (
+            f"BridgeState("
+            f"session={self.session_id}, "
+            f"batch={'set' if self.next_batch else 'unset'}, "
+            f"processed={len(self.processed_event_ids)})"
+        )