Feat: Implement API key authentication (#84)

* feat(auth): Implement API key authentication

This commit enables API access with an API key system. This change provides a better experience for programmatic access and third-party integrations.

Key changes include:
- **API Key Management:** Users can now generate, manage, and revoke persistent API keys through a new "API Keys" section in the settings UI.
- **Authentication Middleware:** API requests are now authenticated via an `X-API-KEY` header instead of the previous `Authorization: Bearer` token.
- **Backend Implementation:** Adds a new `api_keys` database table, along with corresponding services, controllers, and routes to manage the key lifecycle securely.
- **Rate Limiting:** The API rate limiter now uses the API key to identify and track requests.
- **Documentation:** The API authentication documentation has been updated to reflect the new method.

* Add configurable API rate limiting

Two new variables are added to `.env.example`:
- `RATE_LIMIT_WINDOW_MS`: The time window in milliseconds for which requests are checked (defaults to 15 minutes).
- `RATE_LIMIT_MAX_REQUESTS`: The maximum number of requests allowed from an IP within the window (defaults to 100).

The installation documentation has been updated to reflect these new configuration options.

---------

Co-authored-by: Wayne <5291640+ringoinca@users.noreply.github.com>

.env.example

@@ -54,6 +54,12 @@ STORAGE_S3_FORCE_PATH_STYLE=false
 
 # --- Security & Authentication ---
 
+# Rate Limiting
+# The window in milliseconds for which API requests are checked. Defaults to 900000 (15 minutes).
+RATE_LIMIT_WINDOW_MS=900000
+# The maximum number of API requests allowed from an IP within the window. Defaults to 100.
+RATE_LIMIT_MAX_REQUESTS=100
+
 # JWT
 # IMPORTANT: Change this to a long, random, and secret string in your .env file
 JWT_SECRET=a-very-secret-key-that-you-should-change
@@ -64,5 +70,3 @@ JWT_EXPIRES_IN="7d"
 # IMPORTANT: Generate a secure, random 32-byte hex string for this
 # You can use `openssl rand -hex 32` to generate a key.
 ENCRYPTION_KEY=
-
-