Refactor code structure for improved readability and maintainability

backend/app/core/config.py

@@ -20,7 +20,14 @@ class Settings(BaseSettings):
     # and to build redirect URLs from auth routes in the overlay.
     FRONTEND_URL: str = "http://localhost:5173"
 
-    model_config = {"env_file": ".env", "env_file_encoding": "utf-8"}
+    # extra="ignore": tolerate legacy keys (DATA_DIR, SECRET_KEY, DATABASE_URL, …)
+    # left over from pre-split .env files or from the velxio-prod overlay so the
+    # OSS image starts cleanly instead of crashing with extra_forbidden.
+    model_config = {
+        "env_file": ".env",
+        "env_file_encoding": "utf-8",
+        "extra": "ignore",
+    }
 
 
 settings = Settings()

frontend/public/components-metadata.json

@@ -518,7 +518,7 @@
       "description": "Single-channel optocoupler. CTR 80–600% (typ. 100%). Higher drive than 4N25, commonly used for MCU-to-mains isolation."
     },
     {
-      "thumbnail": "<svg width=\"64\" height=\"64\" xmlns=\"http://www.w3.org/2000/svg\">\n      <rect width=\"64\" height=\"64\" fill=\"#1a2332\" rx=\"4\"/>\n      <rect x=\"10\" y=\"14\" width=\"44\" height=\"30\" fill=\"#2a3548\" rx=\"3\" stroke=\"#4a5878\"/>\n      <text x=\"32\" y=\"30\" text-anchor=\"middle\" font-size=\"9\" font-family=\"monospace\" fill=\"#4ade80\" font-weight=\"bold\">5.00V</text>\n      <text x=\"32\" y=\"40\" text-anchor=\"middle\" font-size=\"7\" font-family=\"monospace\" fill=\"#fbbf24\">1.00A</text>\n      <circle cx=\"18\" cy=\"52\" r=\"3\" fill=\"#dc2626\"/>\n      <circle cx=\"46\" cy=\"52\" r=\"3\" fill=\"#0f172a\" stroke=\"#64748b\"/>\n      <text x=\"32\" y=\"60\" text-anchor=\"middle\" font-size=\"6\" fill=\"#9d9d9d\">PSU</text>\n    </svg>",
+      "thumbnail": "<svg width=\"64\" height=\"64\" xmlns=\"http://www.w3.org/2000/svg\">\n      <rect width=\"64\" height=\"64\" fill=\"#e0e0e0\" rx=\"4\"/>\n      <text x=\"50%\" y=\"50%\" text-anchor=\"middle\" dy=\".3em\" font-size=\"10\" fill=\"#666\">\n        POWER-SUPPLY\n      </text>\n    </svg>",
       "tags": [
         "power-supply",
         "regulated",