Add Publisher v2 + 5 extracted skills

Publisher fixes:
- Checkout new branch before push (was pushing main ref)
- Verify files staged before commit
- Handle duplicate files gracefully
- Clean error reporting per stage

Skills merged to main:
- mcp-server-setup (from pipeshub-ai)
- research-pipeline (from Blacknode)
- multi-agent-sequential-workflow (from Fast-LLM-Agent-MCP)
- unifai-workflow-execution (from UnifAI)
- code-review-agent-workflow (from AgentKit)

skills/code-review-agent-workflow/metadata.json

@@ -0,0 +1,24 @@
+{
+  "name": "code-review-agent-workflow",
+  "version": "1.0.0",
+  "goal": "Automate the code review process using a multi-step workflow with human-in-the-loop approval.",
+  "inputs": [
+    "Sample diff of code changes (str)",
+    "Repo context (dict)"
+  ],
+  "steps": [
+    "Step 1: Build the graph for the code review agent using `build_graph()` from `agentkit.workflow.code_review.graph`",
+    "Step 2: Invoke the graph with initial parameters including sample diff, repo context, user ID, and other metadata",
+    "Step 3: The graph processes the input through a series of steps, generating messages and issues as it progresses"
+  ],
+  "outputs": [
+    "Final result containing processed messages and issues (dict)"
+  ],
+  "failure_modes": [
+    "Specific failure scenario with mitigation: If the `build_graph()` function fails to initialize properly, ensure all required dependencies are correctly installed."
+  ],
+  "confidence": 0.95,
+  "explanation": "This workflow is reusable for any code review process that requires a multi-step analysis and human approval.",
+  "source_repo": "https://github.com/itszhaoziyan-n/AgentKit.git",
+  "score": 1.0
+}