docs: deep-audit the API reference pages against code

rest.md: correct the tool response shape (JSON {jobId, downloadUrl, ...} for fast / 202 {jobId, async} for long, not the raw file), fix the SSE jobId source (body, with X-Job-Id only on batch/pipeline ZIP streams), complete the permissions list to all 17, and add ai-canvas-expand.

ai.md: reconcile ~14 AI tool parameter tables to the real Zod schemas (remove-background, upscale, ocr, enhance-faces, colorize, noise-removal, red-eye-removal, restore-photo, passport-photo, erase-object, smart-crop, content-aware-resize, transparency-fixer, image-enhancement), add the 6 missing AI tools (background-replace, blur-background, ocr-pdf, ai-canvas-expand, transcribe-audio, auto-subtitles), and fix the dispatcher script diagram and feature-bundle table.

image-engine.md: add 4 undocumented operations (sharpen, sharpen-advanced, color-blindness, edit-metadata) and fix flip/crop/rotate/convert/compress/strip-metadata/color-channels params, output-format count (13), and the info JSON example. supported-formats.md: output count 14 -> 13. Verified with a clean docs build.

apps/docs/guide/supported-formats.md

@@ -8,7 +8,7 @@ SnapOtter processes files across five modalities: image, video, audio, document,
 
 ## Image Formats
 
-SnapOtter supports 55+ image formats for input and 14 formats for output.
+SnapOtter supports 55+ image formats for input and 13 formats for output.
 
 ## Input Formats
 
@@ -101,7 +101,7 @@ SnapOtter supports 55+ image formats for input and 14 formats for output.
 | PAM | .pam | Sharp (native) | Arbitrary map |
 | PFM | .pfm | Sharp (native) | Float map |
 
-## Output Formats (14)
+## Output Formats (13)
 
 | Format | Encoder | Quality Control | Available In |
 |--------|---------|----------------|-------------|