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/skills/clean/SKILL.md

@@ -0,0 +1,58 @@
+---
+name: security-clean
+description: Scan and remediate security findings — auto-fixes deterministic issues, confirms semi-auto with user, reports manual findings
+---
+
+# Security Clean
+
+Scan, classify, and remediate security findings with user confirmation.
+
+## Step 1: Parse Arguments
+
+- Target path = `$ARGUMENTS` or current working directory
+- `--dry-run` flag = report only, no changes
+
+## Step 2: Create Backup
+
+```bash
+node <plugin-root>/scanners/lib/fs-utils.mjs backup "<target>"
+```
+
+## Step 3: Run Scan
+
+```bash
+node <plugin-root>/scanners/lib/fs-utils.mjs tmppath clean-findings.json
+node <plugin-root>/scanners/scan-orchestrator.mjs "<target>" --output-file "<findings_file>"
+```
+
+Show banner with verdict, risk score, finding counts.
+
+## Step 4: Auto-fix Deterministic Issues
+
+```bash
+node <plugin-root>/scanners/auto-cleaner.mjs "<target>" --findings "<findings_file>" [--dry-run]
+```
+
+Report: Applied, Skipped, Failed counts.
+
+## Step 5: Semi-auto Remediation
+
+For findings classified as semi-auto (entropy strings, permission mismatches, typosquatted deps, ghost hooks, suspicious URLs, credential access, hidden MCP directives, homoglyphs):
+
+1. Read the referenced files and understand the surrounding context
+2. Propose specific, minimal changes grouped by fix type
+3. Present each proposal to the user for confirmation before applying
+4. Apply confirmed changes via Edit tool
+
+## Step 6: LLM Threat Scan
+
+Read `<plugin-root>/knowledge/skill-threat-patterns.md`. Scan modified files for remaining threats. Report manual findings that require human judgment.
+
+## Step 7: Validate and Report
+
+Re-scan to verify fixes didn't introduce new issues. If validation fails, offer to restore from backup:
+```bash
+node <plugin-root>/scanners/lib/fs-utils.mjs restore "<target>"
+```
+
+Final report: pre/post comparison, fix summaries, remaining manual findings, rollback instructions.