Fix deleted modifier-only primary shortcuts staying active

[Yaomeng1749]

Summary

Fixes #498.

Clears stale Primary Dictation hotkey press state when the primary shortcut list changes. This prevents a deleted modifier-only primary shortcut from keeping a pending hold/tap path active until app restart.

Changes

• Track removed primary shortcuts in updatePrimaryShortcuts(_:).
• Clear/cancel matching primary dictation runtime state for removed primary shortcuts.
• Keep event tap teardown as a force-clear path.
• Add a regression test for deleting a modifier-only primary shortcut while its hold start is pending.

Testing

Local:

swiftformat --config .swiftformat Sources/Fluid/Services/GlobalHotkeyManager.swift Tests/FluidDictationIntegrationTests/HotkeyShortcutTests.swift
swiftformat --lint --config .swiftformat Sources/Fluid/Services/GlobalHotkeyManager.swift Tests/FluidDictationIntegrationTests/HotkeyShortcutTests.swift
git diff --check
xcrun swiftc -parse Sources/Fluid/Services/GlobalHotkeyManager.swift Tests/FluidDictationIntegrationTests/HotkeyShortcutTests.swift
swiftlint --strict --config .swiftlint.yml

GitHub Actions, same head c2caabd26d8c2a50daa6f061e78449aa233d8d5e:

• Passing fork CI: https://github.com/Yaomeng1749/FluidVoice/actions/runs/28551228981
• Passed: SwiftLint, dependency resolution, build, tests.

Upstream Actions are awaiting maintainer approval for the public-fork workflow.

[Yaomeng1749]

Final verification for c2caabd26d8c2a50daa6f061e78449aa233d8d5e:

• Added a regression test for deleting a modifier-only Primary Dictation shortcut while its hold start is pending.
• Local Xcode 26.6: swiftlint --strict --config .swiftlint.yml passed with 0 violations.
• Fork CI on the same head passed: https://github.com/Yaomeng1749/FluidVoice/actions/runs/28551228981
• CI covered SwiftLint, dependency resolution, build, and tests.
• Upstream Actions are still waiting for maintainer approval for the public-fork workflow.