feat(navi): deployment profiles + /api/config endpoint

Add profile-driven config infrastructure:
- config/profiles/{home,regional_pi,minimal_pi}.yaml templates
- lib/deployment_config.py loader (reads RECON_PROFILE env var)
- GET /api/config returns active profile as JSON (5min cache)

Frontend reads this on startup to determine tile source, defaults,
and feature flags. No existing behavior changed.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/deployment_config.py

@@ -0,0 +1,46 @@
+"""
+Deployment profile loader.
+
+Reads RECON_PROFILE env var (default: "home"), loads the matching YAML
+from config/profiles/<profile>.yaml, and caches the parsed dict in memory.
+Provides get_deployment_config() for use by the /api/config endpoint.
+"""
+import os
+import yaml
+from .utils import setup_logging
+
+logger = setup_logging('recon.deployment_config')
+
+_config_cache = None
+
+
+def load_deployment_config():
+    """Load and cache the deployment profile. Called once at import time."""
+    global _config_cache
+
+    profile = os.environ.get('RECON_PROFILE', 'home')
+    config_dir = os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), 'config', 'profiles')
+    config_path = os.path.join(config_dir, f'{profile}.yaml')
+
+    if not os.path.exists(config_path):
+        raise FileNotFoundError(
+            f"Deployment profile '{profile}' not found at {config_path}. "
+            f"Available profiles: {', '.join(f.replace('.yaml','') for f in os.listdir(config_dir) if f.endswith('.yaml'))}"
+        )
+
+    with open(config_path, 'r') as f:
+        _config_cache = yaml.safe_load(f)
+
+    logger.info(f"Loaded deployment profile: {profile} ({_config_cache.get('region_name', 'unknown')})")
+    return _config_cache
+
+
+def get_deployment_config():
+    """Return the cached deployment config dict."""
+    if _config_cache is None:
+        load_deployment_config()
+    return _config_cache
+
+
+# Load on import so startup fails fast if profile is missing
+load_deployment_config()