Fix compact notch title spinner alignment

[gitcoder89431]

Codex's braille spinner appeared above the adjacent window-title text in the compact notch on a MacBook at 1.6× display scale. The notch rendered the spinner and title on one baseline even though the spinner uses the upper three rows of an eight-dot braille cell.

Render recognized leading spinner frames separately and align the measured six-dot grid with the font's capital-letter bounds. Measure the full grid for every frame so sparse frames rotate without vertical jitter. Keep the title centered and elided, with ordinary titles rendered intact as plain text.

Validation:

• Compared three spinner frames at 10, 12, 14, and 18 px in a Qt rendering harness.
• Deployed and visually checked the compact notch on the MacBook at its native 1.6× display scale after a full shell restart with a new PID.
• Checked the restarted shell's journal for missing QML types, TypeErrors, binding loops, and plugin fallback.
• qmllint bars/widgets/ruixen.notch/CompactWindowTitle.qml, ./tests/notch-media-viz-mode.sh, ./install.sh --dry-run, and omarchy plugin validate "$HOME/.config/omarchy/plugins/ruixen.notch" passed.
• ./tests/run-all.sh passed.

This PR is independent of #111.