Add documentation for all PDF tools

docs/tools/rotate-custom.md

@@ -0,0 +1,43 @@
+---
+title: Rotate by Custom Degrees
+description: Rotate PDF pages by any angle with per-page degree inputs and batch rotation controls.
+---
+
+# Rotate by Custom Degrees
+
+Rotate PDF pages by any arbitrary angle, not just 90-degree increments. Each page gets its own angle input, and you can apply a single angle to all pages at once using the batch control.
+
+## How It Works
+
+1. Upload a PDF file. Thumbnails render for every page.
+2. Each page has a numeric input field showing its current rotation angle.
+3. Type any degree value (positive or negative) to rotate a specific page, or use the per-page left/right buttons for quick 90-degree adjustments.
+4. Use the **batch angle** input at the top to set a uniform rotation for all pages.
+5. Click the process button to generate the rotated PDF.
+
+## Features
+
+- Free-form degree input per page (any integer value)
+- Batch angle control to set the same rotation on every page
+- Real-time preview of rotation in thumbnails
+- Per-page quick-rotate buttons for 90-degree increments
+- Lazy-loaded thumbnails for performance on large documents
+
+## Use Cases
+
+- Correcting slightly tilted scans by a few degrees
+- Rotating pages to match a non-standard orientation requirement
+- Applying precise rotations to individual pages in a mixed-content document
+- Fine-tuning page angles after an initial bulk rotation
+
+## Tips
+
+- Positive values rotate clockwise, negative values rotate counterclockwise.
+- The batch angle field overwrites all per-page angles when applied. Set individual adjustments after the batch operation if needed.
+- For standard 90/180/270-degree rotations with a simpler interface, use [Rotate PDF](./rotate-pdf).
+
+## Related Tools
+
+- [Rotate PDF](./rotate-pdf)
+- [PDF Multi Tool](./pdf-multi-tool)
+- [Organize & Duplicate](./organize-pdf)