fix(context): persist fallback compaction breaker

hermes_state.py

@@ -758,6 +758,7 @@ CREATE TABLE IF NOT EXISTS sessions (
     handoff_error TEXT,
     compression_failure_cooldown_until REAL,
     compression_failure_error TEXT,
+    compression_fallback_streak INTEGER NOT NULL DEFAULT 0,
     rewind_count INTEGER NOT NULL DEFAULT 0,
     archived INTEGER NOT NULL DEFAULT 0,
     FOREIGN KEY (parent_session_id) REFERENCES sessions(id)
@@ -2295,6 +2296,45 @@ class SessionDB:
                 "clear_compression_failure_cooldown(%s) failed: %s",
                 session_id, exc,
             )
+
+    def get_compression_fallback_streak(self, session_id: str) -> int:
+        """Return the persisted deterministic-fallback streak."""
+        if not session_id:
+            return 0
+        with self._lock:
+            conn = self._conn
+            if conn is None:
+                return 0
+            row = conn.execute(
+                "SELECT compression_fallback_streak FROM sessions WHERE id = ?",
+                (session_id,),
+            ).fetchone()
+        if row is None:
+            return 0
+        value = (
+            row["compression_fallback_streak"]
+            if isinstance(row, sqlite3.Row)
+            else row[0]
+        )
+        try:
+            return max(0, int(value or 0))
+        except (TypeError, ValueError):
+            return 0
+
+    def set_compression_fallback_streak(self, session_id: str, streak: int) -> None:
+        """Persist the deterministic-fallback streak for one session."""
+        if not session_id:
+            return
+        normalized = max(0, int(streak))
+
+        def _do(conn):
+            conn.execute(
+                "UPDATE sessions SET compression_fallback_streak = ? WHERE id = ?",
+                (normalized, session_id),
+            )
+
+        self._execute_write(_do)
+
     # ──────────────────────────────────────────────────────────────────────
     # Compression locks
     # ──────────────────────────────────────────────────────────────────────