docs: add per-tool API documentation and fix parity gaps

- Create 53 per-tool VitePress documentation pages with accurate
  parameters from Zod schemas, example requests, and response formats
- Add root llms.txt for LLM-friendly repo browsing
- Fix OpenAPI spec: add auth and 422 error schemas to
  edit-metadata/inspect and strip-metadata/inspect sub-routes
- Fix tool count inconsistency (52 -> 53) across landing site,
  e2e tests, and local docs
- Rename color-adjustments.ts to adjust-colors.ts to match tool ID
- Update VitePress sidebar with all 8 tool categories and top nav

apps/docs/tools/bulk-rename.md

@@ -0,0 +1,72 @@
+---
+description: Rename multiple files using a pattern template and download as ZIP.
+---
+
+# Bulk Rename
+
+Rename multiple files using a pattern template with placeholders for index, padded index, and original filename. Returns a ZIP archive containing all renamed files.
+
+## API Endpoint
+
+`POST /api/v1/tools/bulk-rename`
+
+Accepts multipart form data with multiple files and a JSON `settings` field.
+
+## Parameters
+
+| Parameter | Type | Required | Default | Description |
+|-----------|------|----------|---------|-------------|
+| pattern | string | No | `"image-{{index}}"` | Naming pattern with placeholders (max 1000 characters) |
+| startIndex | number | No | `1` | Starting index number |
+
+### Pattern Placeholders
+
+| Placeholder | Description | Example |
+|-------------|-------------|---------|
+| `{{index}}` | Sequential number starting from `startIndex` | `1`, `2`, `3` |
+| `{{padded}}` | Zero-padded sequential number | `01`, `02`, `03` |
+| `{{original}}` | Original filename without extension | `photo`, `IMG_001` |
+
+The original file extension is always preserved.
+
+## Example Request
+
+```bash
+curl -X POST http://localhost:1349/api/v1/tools/bulk-rename \
+  -H "Authorization: Bearer si_your-api-key" \
+  -F "file=@photo1.jpg" \
+  -F "file=@photo2.jpg" \
+  -F "file=@photo3.jpg" \
+  -F 'settings={"pattern": "vacation-{{padded}}", "startIndex": 1}'
+```
+
+This produces: `vacation-1.jpg`, `vacation-2.jpg`, `vacation-3.jpg`
+
+Using original filename:
+
+```bash
+curl -X POST http://localhost:1349/api/v1/tools/bulk-rename \
+  -H "Authorization: Bearer si_your-api-key" \
+  -F "file=@IMG_001.jpg" \
+  -F "file=@IMG_002.jpg" \
+  -F 'settings={"pattern": "2024-trip-{{original}}-{{index}}"}'
+```
+
+This produces: `2024-trip-IMG_001-1.jpg`, `2024-trip-IMG_002-2.jpg`
+
+## Example Response
+
+The response is a ZIP file streamed directly (not a JSON response). The response headers are:
+
+```
+Content-Type: application/zip
+Content-Disposition: attachment; filename="renamed-a1b2c3d4.zip"
+```
+
+## Notes
+
+- This tool does not process images. It only renames files and packages them into a ZIP archive.
+- The zero-padding width for `{{padded}}` is determined automatically based on the total number of files (e.g. 100 files would use 3-digit padding: `001`, `002`, etc.).
+- File extensions are preserved from the original filenames.
+- Filenames are sanitized to remove unsafe characters.
+- At least one file must be provided.