feat(llm-security-copilot): port llm-security v5.1.0 to GitHub Copilot CLI

Full port of llm-security plugin for internal use on Windows with GitHub
Copilot CLI. Protocol translation layer (copilot-hook-runner.mjs)
normalizes Copilot camelCase I/O to Claude Code snake_case format — all
original hook scripts run unmodified.

- 8 hooks with protocol translation (stdin/stdout/exit code)
- 18 SKILL.md skills (Agent Skills Open Standard)
- 6 .agent.md agent definitions
- 20 scanners + 14 scanner lib modules (unchanged)
- 14 knowledge files (unchanged)
- 39 test files including copilot-port-verify.mjs (17 tests)
- Windows-ready: node:path, os.tmpdir(), process.execPath, no bash

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

plugins/llm-security-copilot/tests/fixtures/supply-chain/Pipfile.lock

@@ -0,0 +1,14 @@
+{
+  "_meta": {
+    "hash": { "sha256": "abc123" },
+    "pipfile-spec": 6,
+    "requires": { "python_version": "3.11" },
+    "sources": [{ "name": "pypi", "url": "https://pypi.org/simple", "verify_ssl": true }]
+  },
+  "default": {
+    "flask": { "version": "==2.3.0" },
+    "colourama": { "version": "==0.4.6" },
+    "requests": { "version": "==2.31.0" }
+  },
+  "develop": {}
+}