chore: bump version to 4.5.0

Bug fixes:
- Fix inverted pager detection logic (returned error instead of path)
- Fix repo.Clone ignoring destination directory parameter
- Fix sheet loading using append on pre-sized slices
- Clean up partial files on copy failure
- Trim whitespace from editor config

Security:
- Add path traversal protection for cheatsheet names

Performance:
- Move regex compilation outside search loop
- Replace string concatenation with strings.Join in search

Build:
- Remove go:generate; embed config and usage as string literals
- Parallelize release builds
- Add fuzz testing infrastructure

Testing:
- Improve test coverage from 38.9% to 50.2%
- Add fuzz tests for search, filter, tags, and validation

Documentation:
- Fix inaccurate code examples in HACKING.md
- Add missing --conf and --all options to man page
- Add ADRs for path traversal, env parsing, and search parallelization
- Update CONTRIBUTING.md to reflect project policy

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CONTRIBUTING.md

@@ -1,48 +1,14 @@
-CONTRIBUTING
+Contributing
 ============
-Do you want to contribute to `cheat`? There are a few ways to help:
 
-#### Submit a cheatsheet ####
-Do you have a witty bash one-liner to share? [Open a pull-request][pr] against
-the [cheatsheets][] repository. (The `cheat` executable source code lives in
-[cheat/cheat][cheat]. Cheatsheet content lives in
-[cheat/cheatsheets][cheatsheets].)
+Thank you for your interest in `cheat`.
 
-#### Report a bug ####
-Did you find a bug? Report it in the [issue tracker][issues]. (But before you
-do, please look through the open issues to make sure that it hasn't already
- been reported.)
+Pull requests are no longer being accepted, and have been disabled on this
+repository. The maintainer is not currently reviewing or merging external code
+contributions.
 
-#### Add a feature ####
-Do you have a feature that you'd like to contribute? Propose it in the [issue
-tracker][issues] to discuss with the maintainer whether it would be considered
-for merging.
+Bug reports are still welcome. If you've found a bug, please open an issue in
+the [issue tracker][issues]. Before doing so, please search through the
+existing open issues to make sure it hasn't already been reported.
 
-`cheat` is mostly mature and feature-complete, but may still have some room for
-new features. See [HACKING.md][hacking] for a quick-start guide to `cheat`
-development.
-
-#### Add documentation ####
-Did you encounter features, bugs, edge-cases, use-cases, or environment
-considerations that were undocumented or under-documented? Add them to the
-[wiki][]. (You may also open a pull-request against the `README`, if
-appropriate.)
-
-Do you enjoy technical writing or proofreading? Help keep the documentation
-error-free and well-organized.
-
-#### Spread the word ####
-Are you unable to do the above, but still want to contribute? You can help
-`cheat` simply by telling others about it. Share it with friends and coworkers
-that might benefit from using it.
-
-#### Pull Requests ####
-Please open all pull-requests against the `develop` branch.
-
-
-[cheat]: https://github.com/cheat/cheat
-[cheatsheets]: https://github.com/cheat/cheatsheets
-[hacking]: HACKING.md
-[issues]: https://github.com/cheat/cheat/issues 
-[pr]: https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/creating-a-pull-request-from-a-fork
-[wiki]: https://github.com/cheat/cheat/wiki
+[issues]: https://github.com/cheat/cheat/issues