[Ronin-CK]

What changed

Adds single-keystroke keyboard shortcuts to switch capture actions in Ryoshot during the region selection phase, eliminating the need to reach for the mouse:

• s switches to Shot (also 1)
• e switches to Edit (also 2)
• o switches to OCR (also 3)
• f switches to Search (also 4)
• r switches to Record (also 5)

To keep the UI minimal and clutter-free:

• Subtle micro-keycaps appear faintly inside each tab for 1.4 seconds upon launch to help users discover the shortcuts.
• After 1.4 seconds, the keycaps smoothly fade out and their layout width collapses to 0px, keeping the tabs symmetrically centered.

Area

global

How it was tested

1. Launched Ryoshot and verified the 1.4s micro-keycap hint fades out smoothly and the tabs settle into symmetrical centering.
2. Pressed s, e, o, f, and r during selection phase and verified each one instantly activates the corresponding capture action.
3. Verified existing number keys (1 through 5), c (color picker), and Enter (fullscreen capture) continue to function properly.
4. Verified modifier chords (Ctrl+A, Escape, etc.) are preserved.
5. Ran qmllint on both shell.qml and RegionBar.qml (0 errors, 0 warnings).
6. Ran the test suite via node --test lib/*.test.mjs (36/36 tests passed).

Checklist

• One logical change, with a clear [area] scope: summary commit subject.
• Matching CHANGELOG.md updated in the area I touched.
• The git hooks pass locally; I did not use --no-verify.
• Lua parses (luac -p), shell scripts pass bash -n, and QML passes qmllint where applicable.
• No duplicated config, no dead code, no commented-out code, no em-dash.
• Docs updated if behavior or layout changed.