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/research-pipeline/metadata.json

@@ -0,0 +1,26 @@
+{
+  "name": "research-pipeline",
+  "version": "1.0.0",
+  "goal": "Fetch a Wikipedia page, summarise its content using an AI agent, and write the summary to a file.",
+  "inputs": [
+    "URL of the Wikipedia page"
+  ],
+  "steps": [
+    "Step 1: Import necessary modules from `_bootstrap` and `blacknode`: Run `from _bootstrap import NIM_MODEL, require_nim_api_key; import blacknode as bn`",
+    "Step 2: Require NVIDIA NIM API key: Call `require_nim_api_key()` to ensure the API key is set.",
+    "Step 3: Create a graph instance: Initialize `g = bn.Graph()`.",
+    "Step 4: Add nodes for URL, HTTPGet, summarisation, and file writing: `url = g.node('Literal', value='URL of the Wikipedia page'); fetcher = g.node('HTTPGet'); summarise = g.node('LLMAgent', system='You are a technical writer. Summarise the text in 3 bullet points.', model=NIM_MODEL); writer = g.node('FileWrite', path='summary.txt')`",
+    "Step 5: Connect nodes with edges: `url.out('value') >> fetcher.inp('url'); fetcher.out('text') >> summarise.inp('prompt'); summarise.out('text') >> writer.inp('text')`",
+    "Step 6: Cook the graph to execute and get output: `result = g.cook(writer, 'path'); print(f'Summary written to: {result}')`"
+  ],
+  "outputs": [
+    "Path of the summary file"
+  ],
+  "failure_modes": [
+    "If the URL is invalid or unreachable, the HTTPGet node will fail; if the summarisation fails, the output text might be empty"
+  ],
+  "confidence": 0.95,
+  "explanation": "This workflow can be adapted to fetch and summarise any Wikipedia page or similar content source.",
+  "source_repo": "https://github.com/temiroff/Blacknode.git",
+  "score": 1.0
+}