Document the new pdf-view-roll-minor-mode feature:
- Explain it's experimental and off by default
- How to enable it (M-x pdf-view-roll-minor-mode)
- What it does (multiple pages, smooth scrolling)
- How to enable by default via hook
- Customization options (margin size and color)
- Warning about experimental status

Document the major new feature in v1.3.0:
- pdf-view-roll-minor-mode for continuous scrolling (Closes #18, #104)
- pdf-annot-edit command for avy-style annotation editing
- Multi-page isearch, link following, and annotation support
- SyncTeX integration with roll mode
- API changes for package developers

Add automated tests for pdf-roll functionality:
- pdf-roll-page-to-pos utility function
- pdf-roll-page-at-current-pos with various positions
- Customization defaults
- Symbol properties
- Minor mode keymap existence

Fix bug in pdf-roll-margin-color defcustom where the :set
function didn't actually set the variable value.

Update all pdf-tools features to work correctly when
pdf-view-roll-minor-mode is active:

- pdf-isearch: Search across all displayed pages simultaneously
- pdf-links: Link selection works with multiple visible pages
- pdf-annot: Annotations work on correct page, add pdf-annot-edit
  command for avy-style annotation editing
- pdf-sync: SyncTeX jumps work with continuous scroll mode
- pdf-view: Display and navigation functions updated for multi-page
- pdf-util: Coordinate transformation updates for visible pages
- pdf-cache: Simplify prefetch (remove timer indirection)
- pdf-occur: Minor compatibility updates

The mode is experimental. Some features may not interact perfectly
with roll mode. Enable with M-x pdf-view-roll-minor-mode.

API changes:
- pdf-view-active-region now includes page information
- isearch results include page data for multi-page display

Co-authored-by: Daniel Nicolai <dalanicolai@gmail.com>
Co-authored-by: Rahguzar <aikrahguzar@zohomail.eu>
Co-authored-by: Ihor Radchenko <yantar92@gmail.com>
Co-authored-by: NightMachinery <feraidoonmehri@gmail.com>

Add core infrastructure for displaying multiple PDF pages
simultaneously with continuous scrolling. This introduces
pdf-view-roll-minor-mode which can be enabled in any PDF buffer.

The implementation is based on image-roll.el by Daniel Nicolai,
with significant enhancements by Rahguzar for pdf-tools integration.

Key features:
- Smooth pixel-level scrolling across page boundaries
- Multiple pages visible simultaneously
- Integration with pixel-scroll-precision-mode
- Efficient page display/undisplay management

Closes #18, #104

Co-authored-by: Daniel Nicolai <dalanicolai@gmail.com>
Co-authored-by: Rahguzar <aikrahguzar@zohomail.eu>
Co-authored-by: Ihor Radchenko <yantar92@gmail.com>
Co-authored-by: NightMachinery <feraidoonmehri@gmail.com>

Document changes since v1.2.0:
- Replace obsolete registerv-make with cl-defstruct for Emacs 30
- Fix pdf-virtual page link filtering
- Resolve native-comp warnings across multiple files
- Add doas support in autobuild for Alpine/OpenBSD
- Move CI to GitHub Actions