feat(kyberforge): add agent-audit skill (closes #11)

## Why

agent-author produces paired agent definition files (Claude Code .md +
Copilot .agent.md) but had no companion audit skill to validate them.
agent-audit fills that gap, giving the same structured PASS/FAIL report
that skill-audit provides for SKILL.md files.

## Implementation Notes

- validate.sh uses scope detection (walk up for plugin.json / .git) to
  locate the counterpart file and determine whether plugin-silently-ignored
  fields (hooks, mcpServers, permissionMode) should be flagged
- CC-only and silently-ignored field lists are read from
  references/field-inventory.md at runtime rather than hardcoded —
  provenance back to the research corpus; see ADR-0019
- Single-file invocation (pass either file, counterpart derived) chosen
  over directory or name+root — see ADR-0018
- 12 bats tests cover provider detection, scope detection, all FAIL paths,
  and clean-pair pass

## Impact

- kyberforge bumped to v1.1.2
- agent-author close step should be updated to reference agent-audit (#11)
- Provenance/sources chain check deferred to #60

ADR: docs/adr/0018-agent-audit-single-file-invocation.md
ADR: docs/adr/0019-agent-audit-field-inventory-reference.md
Refs: #11
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0147vXtL5sP6vorDdqXGJJU9

plugins/kyberforge/skills/agent-audit/scripts/README.md

@@ -0,0 +1,47 @@
+# scripts/
+
+Executable code bundled with this skill. Agents run scripts in this directory
+to perform repeatable operations rather than reinventing the logic each run.
+
+## When to add a script
+
+Add a script when agents independently reinvent the same logic across runs —
+building the same parser, chart, or validation routine from scratch each time.
+Bundle it here once, tested and reliable.
+
+## Script requirements (agentskills.io)
+
+Scripts must be designed for non-interactive, agentic execution:
+
+- **No interactive prompts** — agents run in non-interactive shells.
+  Accept all input via flags, env vars, or stdin. A script that blocks on
+  TTY input hangs indefinitely.
+- **Expose `--help`** — this is how agents learn your script's interface.
+  Keep the output concise; it enters the agent's context window.
+- **Structured output** — write data (JSON, CSV, TSV) to stdout.
+  Write progress, warnings, and diagnostics to stderr.
+- **Idempotent** — prefer "create if not exists" over "create and fail on
+  duplicate". Agents may retry on failure.
+- **Meaningful exit codes** — `0` for success, non-zero for failure.
+  Use distinct codes for different failure types; document them in `--help`.
+- **Dry-run support** — add `--dry-run` for destructive operations.
+
+## Self-contained scripts
+
+Bundle dependencies inline so the agent can run the script with a single command.
+
+Python (PEP 723 + uv):
+```python
+# /// script
+# dependencies = ["requests>=2.31,<3"]
+# requires-python = ">=3.11"
+# ///
+import requests
+```
+```bash
+uv run scripts/my-script.py
+```
+
+## If no scripts are needed
+
+Delete this README and the `scripts/` directory entirely.