refactor(skills): migrate skills to agent-skills-nix

- Remove local skills directory from git tracking
- Add agent-skills-nix and StackOneHQ/skills as flake inputs
- Configure devShell to auto-install skills via symlink-tree
- Update .gitignore to exclude Nix-managed skill directories
- Update CLAUDE.md to document the new skills management approach

Skills are now sourced from StackOneHQ/skills repository and
automatically installed when entering `nix develop`.

Author: ryoppippi

.claude/skills/orama-integration/SKILL.md

@@ -181,3 +181,8 @@ dist
 .direnv
 !.envrc
 
+# Agent skills (managed by Nix via agent-skills-nix)
+.claude/skills
+.codex/skills
+.opencode/skills
+

.claude/skills/release-please/SKILL.md

@@ -5,7 +5,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 ## Rules and Skills Structure
 
 - **Rules** (`.claude/rules/`): Automatically loaded based on file paths. Source of truth for project conventions.
-- **Skills** (`.claude/skills/`): Manually invoked for specific integrations.
+- **Skills** (`.claude/skills/`): Managed by Nix via [agent-skills-nix](https://github.com/Kyure-A/agent-skills-nix). Skills are sourced from [StackOneHQ/skills](https://github.com/StackOneHQ/skills) and installed automatically when entering `nix develop`.
 - **Cursor rules** (`.cursor/rules/`): Symlinks to `.claude/rules/` for consistency.
 
 ## Available Rules

.gitignore

@@ -3,23 +3,67 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+
+    # Agent skills management
+    agent-skills.url = "github:Kyure-A/agent-skills-nix";
+    agent-skills.inputs.nixpkgs.follows = "nixpkgs";
+
+    # StackOne skills repository (non-flake)
+    stackone-skills.url = "github:StackOneHQ/skills";
+    stackone-skills.flake = false;
   };
 
   outputs =
-    { nixpkgs, ... }:
+    {
+      nixpkgs,
+      agent-skills,
+      stackone-skills,
+      ...
+    }:
     let
       systems = [
         "x86_64-linux"
         "aarch64-linux"
         "aarch64-darwin"
       ];
       forAllSystems = nixpkgs.lib.genAttrs systems;
+
+      # Agent skills configuration
+      agentLib = agent-skills.lib.agent-skills;
+      sources = {
+        stackone = {
+          path = stackone-skills;
+          subdir = ".";
+        };
+      };
+      catalog = agentLib.discoverCatalog sources;
+      allowlist = agentLib.allowlistFor {
+        inherit catalog sources;
+        enable = [
+          "orama-integration"
+          "release-please"
+        ];
+      };
+      selection = agentLib.selectSkills {
+        inherit catalog allowlist sources;
+        skills = { };
+      };
     in
     {
       devShells = forAllSystems (
         system:
         let
           pkgs = nixpkgs.legacyPackages.${system};
+          bundle = agentLib.mkBundle { inherit pkgs selection; };
+          # Use symlink-tree instead of copy-tree for skills
+          localTargets = {
+            claude = {
+              dest = ".claude/skills";
+              structure = "symlink-tree";
+              enable = true;
+              systems = [ ];
+            };
+          };
         in
         {
           default = pkgs.mkShellNoCC {
@@ -47,13 +91,17 @@
 
               # Install dependencies only if node_modules/.pnpm/lock.yaml is older than pnpm-lock.yaml
               if [ ! -f node_modules/.pnpm/lock.yaml ] || [ pnpm-lock.yaml -nt node_modules/.pnpm/lock.yaml ]; then
-                echo "📦 Installing dependencies..."
+                echo "Installing dependencies..."
                 pnpm install --frozen-lockfile
               fi
 
               # Install lefthook git hooks
               lefthook install > /dev/null 2>&1
-            '';
+            ''
+            + agentLib.mkShellHook {
+              inherit pkgs bundle;
+              targets = localTargets;
+            };
           };
         }
       );