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"

.pre-commit-config.yaml

@@ -0,0 +1,27 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+      - id: trailing-whitespace
+        exclude: \.md$
+      - id: end-of-file-fixer
+      - id: check-yaml
+      - id: check-toml
+      - id: check-added-large-files
+      - id: check-merge-conflict
+
+  - repo: local
+    hooks:
+      - id: fmt
+        name: cargo fmt
+        entry: cargo fmt
+        args: ["--", "--check"]
+        language: system
+        types: [rust]
+        pass_filenames: false
+      - id: clippy
+        name: cargo clippy
+        entry: cargo clippy
+        args: ["--", "-D", "warnings"]
+        language: system
+        pass_filenames: false