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

home/terminal/software/git.nix

@@ -5,7 +5,40 @@
 }: let
   configFile = "git/config";
   ignoreFile = "git/ignore";
+  hooksDir = "git/hooks";
   toINI = (pkgs.formats.ini {}).generate;
+
+  # Hook that auto-generates a Conventional Commit message from staged diff
+  prepareCommitMsg = pkgs.writeShellScript "prepare-commit-msg" ''
+    # Only run if there are staged changes
+    if git diff --cached --quiet 2>/dev/null; then
+      exit 0
+    fi
+
+    echo "Generating commit message from staged changes..." >&2
+
+    # Generate Conventional Commit message using opencode run
+    git diff --cached | timeout 30 ${pkgs.opencode}/bin/opencode run \
+      -m opencode/north-mini-code-free \
+      "You are an expert software engineer writing professional Git commit messages.
+
+Create a clean Conventional Commit for the provided diff.
+
+Rules:
+- Format: type(optional scope): imperative description
+- Allowed types: feat, fix, docs, style, refactor, perf, test, build, ci, chore
+- First line: maximum 72 characters, starts with capital letter, imperative present tense
+- If relevant, add a blank line followed by a short body explaining the motivation and key changes
+- Be concise and professional. No emojis, no markdown.
+
+Output ONLY the commit message. Do not add any extra text, quotes, or explanations." \
+      2>/dev/null > "$1"
+
+    # Fallback if generation failed or timed out
+    if [ ! -s "$1" ]; then
+      echo "chore: auto-generated commit message" > "$1"
+    fi
+  '';
 in {
   users.users.someone.packages = with pkgs; [
     git
@@ -36,6 +69,7 @@ in {
     };
     core = {
       editor = "nvim";
+      hooksPath = "${config.xdg.configHome}/git/hooks";
       pager = "${pkgs.delta}/bin/delta";
       whitespace = "fix,-indent-with-non-tab,trailing-space,cr-at-eol";
       excludesFile = "${config.xdg.configHome}/${ignoreFile}";
@@ -124,4 +158,6 @@ in {
     AGENTS.md
     .sisyphus
   '';
+
+  xdg.configFile."${hooksDir}/prepare-commit-msg".source = prepareCommitMsg;
 }