Stop API key save() from writing other providers' keys as plaintext (#1944)

save() called load(), which DECRYPTS every stored key, then re-encrypted
only the key being saved and wrote the whole dict back. The other
providers' keys were thus persisted in plaintext; on the next load()
Fernet raised InvalidToken on them and they were silently dropped.

Add _load_raw() that returns the still-encrypted on-disk dict (reusing the
existing missing/corrupt-file guards) and have save() build on that, so
untouched providers keep their ciphertext. load() now also goes through
_load_raw(), keeping its behavior identical.

Fixes #1914

Co-authored-by: EkaTantra Dev <dev@ekatantra.com>

src/api_key_manager.py

@@ -37,15 +37,12 @@ class APIKeyManager:
         f = Fernet(self.get_or_create_key())
         return f.decrypt(encrypted_key.encode()).decode()
     
-    def save(self, provider: str, api_key: str):
-        """Save encrypted API key to file"""
-        keys = self.load()
-        keys[provider] = self.encrypt_api_key(api_key)
-        with open(self.api_keys_file, 'w', encoding="utf-8") as f:
-            json.dump(keys, f)
-    
-    def load(self) -> Dict[str, str]:
-        """Load and decrypt API keys"""
+    def _load_raw(self) -> Dict[str, str]:
+        """Load the raw, still-encrypted keys dict from disk.
+
+        Tolerates a missing/corrupt/wrong-shaped file by returning {} — the
+        same robustness load() relies on at startup.
+        """
         if not os.path.exists(self.api_keys_file):
             return {}
         try:
@@ -60,7 +57,24 @@ class APIKeyManager:
             # Legacy/wrong shape (e.g. a list) — .items() would raise. Ignore it.
             logger.warning("API keys file has unexpected shape (%s); ignoring", type(encrypted_keys).__name__)
             return {}
+        return encrypted_keys
 
+    def save(self, provider: str, api_key: str):
+        """Save encrypted API key to file.
+
+        Operates on the raw (still-encrypted) on-disk dict so other providers'
+        keys stay encrypted. Loading via load() first would decrypt them and
+        write them back as plaintext, which then fails to decrypt on the next
+        load() and silently drops those providers.
+        """
+        keys = self._load_raw()
+        keys[provider] = self.encrypt_api_key(api_key)
+        with open(self.api_keys_file, 'w', encoding="utf-8") as f:
+            json.dump(keys, f)
+
+    def load(self) -> Dict[str, str]:
+        """Load and decrypt API keys"""
+        encrypted_keys = self._load_raw()
         decrypted = {}
         for provider, key in encrypted_keys.items():
             try: