fix: encryption and other fixes

[TEJASNARAYANS]

What Changed?

Encryption key persistence across CLI/Docker: Replaced Docker named volume with a shared .data/ directory bind mount so both CLI and Docker read/write the same encryption key file. New keys are saved to .data/.encryption_key with fallback to the legacy .encryption_key for backward compatibility.

Worker network_mode: host removal: Removed unnecessary network_mode: host from the worker service, which was preventing it from resolving Docker service names (db, redis) and causing DB connectivity failures. Both API and worker now share the same bridge network and config.docker.yml.

API key whitespace stripping: Added .strip() on both encrypt and decrypt paths to prevent accidental leading/trailing whitespace from corrupting API keys. This fixed a Vapi 400 "failed to extract key" error caused by a leading space in the stored API key.

Vapi error diagnostics: Improved retrieve_call_metrics to capture and log Vapi's actual error response body before raising, instead of only logging the HTTP status code. Also removed unnecessary Content-Type: application/json header from GET requests.

Frontend error surfacing: Updated frontend catch blocks for Retell, Vapi, and ElevenLabs to extract error.response.data.detail for toast notifications instead of showing generic Axios errors. Backend was also updated to pass through human-readable provider error messages (e.g., "Trial over quota, please add payment.").

Deleted redundant config: Removed config.docker.worker.yml (separate worker config with localhost URLs) since the worker no longer needs network_mode: host. Reverted app/config.py env var override logic that was only needed for the host networking workaround.

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Checklist

• I have read the CONTRIBUTING.md guide.
• My code follows the project's style guidelines.
• I have added tests that prove my fix is effective or my feature works.
• I have updated documentation where needed.