feat(github): add auto-conventional-commit hook with opencode integration

- Add prepare-commit-msg git hook that generates conventional commit messages
- Modularize fish configuration with separate conf.d files
- Convert configuration files from .text to .source format for structured data
- Add sops-nix SOPS configuration with explicit secret definitions
- Upgrade age identity to single key file management approach
- Add system activation script for age key management
- Generate .sops.yaml for SOPS creation rules
- Restructure README.md with improved table and cleaner formatting
- Refactor config files to use pkgs.formats.json/toml generators
- Implement YAML format for ashell and walker service configurations
- Update SSH config source to use sops secrets
- Convert zed and other config files to use structured .source format

.sops.yaml

@@ -0,0 +1,3 @@
+creation_rules:
+  - path_regex: secrets/secrets\.yaml$
+    age: age1vtlutzzhgsy4ef8jd97jaay30zwygj68jwgn0zx64m2d5u57sqzsngy7lf