test: cover critical regression paths

[vibhor1102]

Summary

Adds regression coverage for critical paths across gesture execution, database migrations, scenario backup import, counters, actions, conditions, events, and scenario editing.

The branch targets dev-4.0.0-beta08-fixes and contains the test commit only. The temporary hosted verification workflow used during validation was removed before opening this PR.

Findings from verification

The hosted verification run executed the independent test tasks and exposed four failures. The tests appear valid and are intentionally left unfixed for maintainer review:

• A late gesture callback can complete the next gesture after a timeout.
• Migration 19 to 20 does not actually process lowercase persisted enum values despite normalizing them in Kotlin.
• Current-version smart backup imports reject unknown nested fields despite the forward-compatibility intent.
• The counter creation command can add a whitespace-only counter when called directly, although the normal UI disables Save.

These findings are tracked in #1046. This PR adds the regression tests only; production fixes are intentionally left for separate maintainer follow-up.

Validation

Hosted verify run: https://github.com/vibhor1102/Smart-AutoClicker/actions/runs/31606697584

The run used the temporary verify-only workflow and reported the four test failures above. No local Gradle tests were run because repository guidance prohibits local compilation/testing on this machine.

[Nain57]

Other comments can be found here #1046

Part of this commit have been integrated with their fixes: #1043

[vibhor1102]

Thanks for the review. I have updated the PR accordingly:

• rebased and retargeted it onto master;
• removed the GestureExecutor and counter-creation tests now covered by Bugfixes 4.0.0-beta08 #1043;
• removed the lowercase migration, unknown backup field, and Room auto-migration tests;
• restored the complete legal headers in the affected files.

The remaining eight test files passed the hosted unit-test workflow: https://github.com/vibhor1102/Smart-AutoClicker/actions/runs/32147825321