feat(plugins): scaffold git, gitea, and core plugins

Adds three new plugins to the holocron marketplace:
- git: 4 stub skills (git-commit, git-branch, git-pr, git-flow)
- gitea: 5 stub skills (gitea-issues, gitea-prs, gitea-milestones, gitea-releases, gitea-wiki)
- core: 5 stub skills (triage, diagnose, zoom-out, caveman, improve-codebase-architecture)

All plugins follow version-parity convention (ADR-0016). Skills are
placeholder stubs — content will be authored in a future workstream.
Registered in both marketplace.json paths.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

plugins/git/.claude-plugin/plugin.json

@@ -0,0 +1,17 @@
+{
+  "author": {
+    "name": "Defame1297",
+    "url": "https://git.dev.rkdr.net/Defame1297/"
+  },
+  "description": "Skills for working with Git \u2014 conventional commits, branch management, pull requests, and feature flow.",
+  "displayName": "Git",
+  "keywords": [
+    "git",
+    "vcs",
+    "commit",
+    "branch"
+  ],
+  "license": "MIT",
+  "name": "git",
+  "version": "1.0.0"
+}

plugins/git/plugin.json

@@ -0,0 +1,22 @@
+{
+  "agents": "agents/",
+  "author": {
+    "email": "defame1297@rkdr.net",
+    "name": "Defame1297"
+  },
+  "description": "Skills for working with Git \u2014 conventional commits, branch management, pull requests, and feature flow.",
+  "hooks": "hooks.json",
+  "keywords": [
+    "git",
+    "vcs",
+    "commit",
+    "branch"
+  ],
+  "license": "MIT",
+  "mcpServers": ".mcp.json",
+  "name": "git",
+  "skills": [
+    "skills/"
+  ],
+  "version": "1.0.0"
+}

plugins/git/skills/git-branch/SKILL.md

@@ -0,0 +1,10 @@
+---
+name: git-branch
+description: >
+  Use when you want to create, switch, rename, or delete git branches.
+  Stub — full content not yet written.
+metadata:
+  category: implement
+---
+
+> **Stub.** This skill is a placeholder. Content will be authored in a future workstream.

plugins/git/skills/git-commit/SKILL.md

@@ -0,0 +1,10 @@
+---
+name: git-commit
+description: >
+  Use when you want to commit staged changes following conventional commit
+  format (feat:, fix:, docs:, chore:, etc.). Stub — full content not yet written.
+metadata:
+  category: implement
+---
+
+> **Stub.** This skill is a placeholder. Content will be authored in a future workstream.

plugins/git/skills/git-flow/SKILL.md

@@ -0,0 +1,10 @@
+---
+name: git-flow
+description: >
+  Use when you want to follow a complete git feature-branch workflow from
+  branch creation through merge. Stub — full content not yet written.
+metadata:
+  category: implement
+---
+
+> **Stub.** This skill is a placeholder. Content will be authored in a future workstream.

plugins/git/skills/git-pr/SKILL.md

@@ -0,0 +1,10 @@
+---
+name: git-pr
+description: >
+  Use when you want to open, review, or merge a pull request via the git
+  host CLI. Stub — full content not yet written.
+metadata:
+  category: implement
+---
+
+> **Stub.** This skill is a placeholder. Content will be authored in a future workstream.