Fetch remote config and detect config changes for auto-refresh

- Pulls frame_config from BirdNET server API each timer cycle
- Remote settings override local config.toml (except paths/base_url)
- Display-affecting config changes (title, saturation, rotate, sizes)
  are tracked via a config signature in state.json
- Config change forces a panel refresh on the next cycle

Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>

frame/display.py

@@ -133,6 +133,34 @@ def _today_hours(cfg):
     return max(1, hours)
 
 
+def fetch_remote_config(base, timeout, auth=None):
+    """Fetch frame config from the BirdNET server's frame_config endpoint."""
+    url = f"{base.rstrip('/')}/avian/api/birdnet-api.php?action=frame_config"
+    req = urllib.request.Request(url, headers={"User-Agent": "AvianVisitors-frame/1.0"})
+    if auth:
+        req.add_header("Authorization", auth)
+    try:
+        with urllib.request.urlopen(req, timeout=timeout) as r:
+            return json.loads(r.read(100_000))
+    except Exception as e:
+        print(f"remote config fetch failed: {e}", file=sys.stderr)
+        return None
+
+
+DISPLAY_KEYS = (
+    "mode", "hours", "start_time", "shoot_title", "shoot_subtitle",
+    "shoot_headline_px", "shoot_eyebrow_px", "shoot_lowercase",
+    "shoot_mat", "shoot_small_floor", "shoot_count_exp",
+    "mat", "mat_opening_w", "mat_opening_h", "rotate", "saturation",
+)
+
+
+def config_signature(cfg):
+    """Hash of display-affecting config values."""
+    items = [(k, cfg.get(k)) for k in DISPLAY_KEYS]
+    return hashlib.sha256(json.dumps(items).encode()).hexdigest()[:16]
+
+
 # --- image ------------------------------------------------------------------
 def get_image(src, timeout, auth=None):
     if re.match(r"^https?://", src):
@@ -319,15 +347,15 @@ def load_state(path):
         with open(os.path.expanduser(path)) as f:
             return json.load(f)
     except Exception:
-        return {"signature": None, "last_refresh": 0}
+        return {"signature": None, "last_refresh": 0, "config_sig": None}
 
 
-def save_state(path, sig, when):
+def save_state(path, sig, when, cfg_sig=None):
     path = os.path.expanduser(path)
     os.makedirs(os.path.dirname(path) or ".", exist_ok=True)
     tmp = path + ".tmp"
     with open(tmp, "w") as f:
-        json.dump({"signature": sig, "last_refresh": when}, f)
+        json.dump({"signature": sig, "last_refresh": when, "config_sig": cfg_sig}, f)
         f.flush()
         os.fsync(f.fileno())
     os.replace(tmp, path)  # atomic: a power cut can't leave a half-written file
@@ -370,6 +398,11 @@ def obtain_image(cfg, species=None, window_hours=None):
 
 def run(cfg, preview=None, force=False, use_signature=True, mat_box=False):
     now = time.time()
+    remote = fetch_remote_config(cfg["base_url"], cfg["timeout"], _auth(cfg))
+    if remote:
+        for k, v in remote.items():
+            if k in cfg and k not in ("state", "cache", "base_url"):
+                cfg[k] = v
     state = load_state(cfg["state"])
     sig = None
     species = None
@@ -388,8 +421,12 @@ def run(cfg, preview=None, force=False, use_signature=True, mat_box=False):
             sig = signature(species)
         except Exception as e:
             print(f"signature fetch failed: {e}", file=sys.stderr)  # treat as no change
+    cfg_sig = config_signature(cfg)
+    config_changed = cfg_sig != state.get("config_sig")
+    if config_changed and not force and not preview:
+        print("config changed; forcing refresh")
     heal_due = now - state.get("last_refresh", 0) >= cfg["heal_hours"] * 3600
-    changed = (not use_signature) or (sig is not None and sig != state.get("signature"))
+    changed = config_changed or (not use_signature) or (sig is not None and sig != state.get("signature"))
     if not force and not preview:
         if in_quiet_hours(cfg, datetime.now().hour):
             print("quiet hours; skip")
@@ -418,7 +455,7 @@ def run(cfg, preview=None, force=False, use_signature=True, mat_box=False):
     except Exception as e:
         print(f"panel push failed: {e}", file=sys.stderr)
         return
-    save_state(cfg["state"], sig if sig is not None else state.get("signature"), now)
+    save_state(cfg["state"], sig if sig is not None else state.get("signature"), now, cfg_sig)
     print("panel updated")