feat: peek-to-reveal on click/ctrl, pre-commit hooks, devShell, fmt fixes

- Click indicator ring to toggle password peek (persistent click-to-toggle)
- Ctrl-hold transient peek refactored to share peek path
- Cursor always visible (previously hidden at position 0, now shows at top of ring)
- .pre-commit-config.yaml: standard hooks + cargo fmt/clippy
- flake.nix: devShell with cargo, rustc, rustfmt, clippy, cargo-audit, prek
- cargo fmt pass across all source files (trailing whitespace, line wrapping)
- MPRIS error logging (silent failures now logged)
- Dependabot versioning-strategy: "increase" → "auto"

.github/PULL_REQUEST_TEMPLATE.md

@@ -20,4 +20,4 @@ Please describe the tests that you ran to verify your changes.
 - [ ] I have made corresponding changes to the documentation
 - [ ] My changes generate no new warnings
 - [ ] I have added tests that prove my fix is effective or that my feature works
-- [ ] New and existing unit tests pass locally with my changes
+- [ ] New and existing unit tests pass locally with my changes