fix(a11y): screen readers and the keyboard

[hazeliscoding]

The first v1.1.1 item from the 2026-10-10 accessibility audit. This PR also adds the v1.1.1 milestone to ROADMAP.md.

• Rating: takes Tab focus with a teal ring. The arrows step it, Home and End jump to the ends, 0–5 pick a value, and Delete clears it. Screen readers read it as a "Usefulness" slider whose value is the rating's word, such as "Solid".
• Toasts and Quick save's error are live regions. Each stays in the window and takes the message as its name.
  • Avalonia 12.1.3's peers don't report a name change, and that's what its Windows backend raises LiveRegionChanged on. AccessibleNames now reports it for live regions.
  • Checked with UI Automation against a scratch copy on Windows: the error and a toast each raised LiveRegionChanged, with their own text as the element's name.
  • Avalonia 12.1.3’s Linux accessibility backend (AT-SPI) has no live-region support, so Linux doesn’t announce these yet.
• Hearts read "Add to favorites" or "Remove from favorites", where all of them used to read "Favorite".
• Show details switches to "Hide details", with a downward chevron, once the details are open.
• Workflows: the Run tab's Previous and Next buttons point left and right, to match the step strip. This adds Lucide's arrow-left to the generated icons.
• User guide: mentions rating from the keyboard.

Tests:

• New in AccessibilityTests: the rating from the keyboard, both announcers (live setting, name, and the name-changed event), the heart's names, and Show details.
• Full suite on the last commit: all passed. The performance tests ran on their own; run alongside the UI tests, two of them miss their time limit on this machine.
• Each commit in between builds and passes AccessibilityTests.