Add octofriend configuration to flake

- Embed octofriend.json5 config directly in flake.nix postInstall
- Set OCTOFRIEND_CONFIG_DIR to point to included config
- Add comprehensive README with setup and configuration instructions
- Keep API keys out of repo for security (users must add keys.json5 locally)

appflakes/octofriend/README.md

@@ -0,0 +1,64 @@
+# Octofriend flake for Nix/NixOS
+
+This flake packages [octofriend](https://github.com/synthetic-lab/octofriend), a CLI coding assistant.
+
+## Building
+
+```bash
+nix build .
+```
+
+## Running
+
+```bash
+nix run .
+```
+
+## Installation
+
+Add to your NixOS configuration:
+```nix
+inputs.octofriend.url = "path:/home/jsutter/src/nixos/appflakes/octofriend";
+
+# Then in your environment.systemPackages or home.packages:
+self.inputs.octofriend.packages.${system}.default
+```
+
+## Configuration
+
+The octofriend flake includes default configuration files at `/share/octofriend/config/octofriend.json5`. However, API keys should not be stored in the repository for security reasons.
+
+### Default Configuration
+
+The included configuration provides:
+- Your name as 'Jules'
+- Two model configurations (GLM-4.6 and MiniMax M2) pointing to https://api.synthetic.new
+- Specialized models for diff-apply and fix-json operations
+
+### API Keys
+
+To configure API keys, create a `keys.json5` file in your configuration directory:
+```json5
+{
+  'https://api.synthetic.new/v1': 'your-api-key-here'
+}
+```
+
+When using octofriend, you can either:
+1. Place your keys in `~/.config/octofriend/keys.json5` (default location)
+2. Set the `OCTOFRIEND_CONFIG_DIR` environment variable to a custom directory containing your files
+
+This ensures sensitive API keys are not committed to the repository while still providing functional default configuration.
+
+### Custom Configuration
+
+If you want to override the default configuration, you can create your own `octofriend.json5` file in your config directory. The wrapper script will check for configuration files in the following order:
+1. `$OCTOFRIEND_CONFIG_DIR/octofriend.json5` (if OCTOFRIEND_CONFIG_DIR is set)
+2. `~/.config/octofriend/octofriend.json5`
+3. Fall back to the included default at `$OCTOFRIEND_PACKAGE_DIR/share/octofriend/config/octofriend.json5`
+
+## Security Note
+
+- The `keys.json5` file containing API keys is intentionally NOT included in this flake
+- Never commit API keys to any repository
+- The included configuration uses placeholder settings and should be customized with your actual model preferences and endpoints