[enaboapps]

Auto scan rate now has accessible − / value / + controls, with each press adjusting the interval by 0.1 seconds within 0.1–10 seconds. The scanning menu’s Faster/Slower actions use the same increments. Existing rates, including 0.25 and 0.75 seconds, remain valid and are adjusted without rounding.

Shared and point/menu/keyboard settings retain their inheritance, reset and manual-mode behaviour. Backend validation accepts the expanded range; existing defaults, settings schema, line speed, auto-select delay and BLE remain unchanged.

Validation:

• Frontend lint, production build, 163 frontend tests and 5 script tests passed.
• Rust format, Clippy, 483 unit tests and 7 configuration tests passed; one existing ignored benchmark. Documentation tests passed after rerunning following a shared build-cache conflict.
• Regression coverage includes interval bounds, legacy values, persistence, per-area resolution, manual-mode retention/reset and menu increments/override scope.
• Independent review of 870745e: no actionable findings.
• Mac VM: observed disabled controls in manual mode; enabled automatic mode and verified 0.5 → 0.6 → 0.5 seconds using +/−.
• Windows ARM VM: native build and launch passed. Parallels did not deliver automated clicks/Tab to the settings window, so Windows control interaction and native timing validation remain unverified. Automated tests cover timing configuration and adjustments; no claim of complete native timing qualification.
• Both VMs’ settings restored byte-for-byte; prior Windows build restarted and Mac VM returned to suspended. Signed local Mac app remained untouched.
• All CI checks passed, including native Mac and Windows packaging (run 35525787268).

Closes #809. Merge and release require separate instructions.