feat: add nixos-asset-manager skill

skills/nixos-workflow/SKILL.md

@@ -0,0 +1,50 @@
+---
+name: nixos-asset-manager
+description: Manage Pi agent assets (extensions, skills, themes, prompts) on NixOS with Gitea synchronization.
+version: 1.0.0
+---
+
+# NixOS Asset Manager
+
+This skill guides the agent in maintaining a declarative, Gitea-backed configuration for the Pi coding agent on NixOS.
+
+## Core Principles
+
+1.  **Source of Truth**: All custom code (extensions), instructions (skills), and UI assets (themes) must be saved in `~/ai-assets`.
+2.  **No Direct Nix Store Writes**: Never attempt `pi install npm:...` or global `npm install` as it fails on NixOS. Always clone sources into `~/ai-assets/extensions` and run `npm install` locally within that folder.
+3.  **Gitea Sync**: After any local modification to `~/ai-assets`, the agent must commit and push changes to `https://audasmedia.com.au`.
+4.  **Configuration Layering**:
+    *   **Global**: Referenced via `home.nix` in the `~/.pi/agent/settings.json` file.
+    *   **Project-Specific**: Defined in `.pi/settings.json` within individual project folders to avoid "bloat."
+
+## File Structure Standards
+
+The agent must maintain the following structure in `~/ai-assets`:
+
+- `extensions/`: TypeScript modules (e.g., `steel-browser/index.ts`).
+- `skills/`: Markdown instructions (e.g., `system-architect/SKILL.md`).
+- `themes/`: JSON theme definitions.
+- `prompts/`: Markdown slash-command templates.
+
+## Workflows
+
+### Adding a New Extension
+1.  Navigate to `~/ai-assets/extensions`.
+2.  Clone the repository: `git clone <url> <name>`.
+3.  Remove internal Git tracking to avoid submodules: `rm -rf <name>/.git <name>/.gitignore`.
+4.  Install dependencies locally: `cd <name> && npm install`.
+5.  Update the project's `.pi/settings.json` to include `"extensions/ <name>/index.ts"`.
+6.  Push to Gitea.
+
+### Updating a Skill
+1.  Modify the relevant `.md` file in `~/ai-assets/skills/`.
+2.  Push to Gitea.
+3.  The change is live across all NixOS machines upon the next Pi launch.
+
+### Managing Settings via Nix
+When instructions involve global changes, the agent must remind the user to update the `home.file.".pi/agent/settings.json".text` block in their Home Manager configuration.
+
+## Critical Guardrails
+- **DO NOT** use `~/.agents/skills` as it bypasses Gitea version control.
+- **ALWAYS** check for an existing `.git` folder in new extensions before pushing to Gitea.
+- **NEVER** push `auth.json` or `sessions/` to Gitea.