fix(embed): skip profile .env overwrite when config has no HINDSIGHT_API_* keys (#896)

When the daemon is already running, ensure_running() calls _register_profile()
with a config dict using short keys (llm_api_key, llm_provider, etc.) that do
not match the HINDSIGHT_API_* prefix filter. This caused api_config to always
be empty, and create_profile() would overwrite the existing .env with an empty
file on every CLI command.

Add an early return guard so _register_profile() skips the create_profile()
call when api_config is empty, preserving any existing profile configuration.

Fixes #894

hindsight-embed/hindsight_embed/daemon_embed_manager.py

@@ -419,6 +419,8 @@ class DaemonEmbedManager(EmbedManager):
         """
         try:
             api_config = {k: v for k, v in config.items() if k.startswith("HINDSIGHT_API_")}
+            if not api_config:
+                return
             self._profile_manager.create_profile(profile, port, api_config)
         except Exception as e:
             logger.debug(f"Failed to register profile '{profile}' in metadata: {e}")