docs: audit all 157 tool pages against live schemas

Reconcile every tool page's parameters, defaults, and response shape against the tool's Zod settings schema and executionHint in code. Notable fixes: color-palette (add count + format params, hex output, median-cut algorithm), favicon (add 5 params, was documented as having none), qr-generate (add logoDataUri), convert (add ppm/eps/tga formats), video-loudnorm (-16 LUFS not -14), smart-crop (async 202 not sync 200), images-to-video (1080x1080 square), and several output-filename and behavior-note corrections.

Also normalize API endpoint paths to /api/v1/tools/<id> (no modality segment) and standardize curl examples on the Docker API port 1349. Verified with a clean docs build.

apps/docs/tools/audio/fade-audio.md

@@ -8,7 +8,7 @@ Add fade-in and fade-out effects to the beginning and end of an audio file.
 
 ## API Endpoint
 
-`POST /api/v1/tools/audio/fade-audio`
+`POST /api/v1/tools/fade-audio`
 
 Accepts multipart form data with an audio file and a JSON `settings` field.
 
@@ -22,7 +22,7 @@ Accepts multipart form data with an audio file and a JSON `settings` field.
 ## Example Request
 
 ```bash
-curl -X POST http://localhost:1349/api/v1/tools/audio/fade-audio \
+curl -X POST http://localhost:1349/api/v1/tools/fade-audio \
   -H "Authorization: Bearer si_your-api-key" \
   -F "file=@audio.mp3" \
   -F 'settings={"fadeInS": 2, "fadeOutS": 3}'
@@ -41,6 +41,6 @@ curl -X POST http://localhost:1349/api/v1/tools/audio/fade-audio \
 
 ## Notes
 
-- Set either value to `0` to skip that fade direction.
-- The fade duration should not exceed the audio length.
+- Set either value to `0` to skip that fade direction. At least one must be greater than 0.
+- The fade duration is clamped to the audio length if it exceeds it.
 - Output format matches the input format.