feat(core): add agentsmd-audit skill

Audits a target repo's AGENTS.md file(s) for embedded secrets, structural
completeness against the agents.md common-sections checklist, and drift
(referenced commands/paths that no longer resolve). First active skill in
the core plugin — kyberforge is scoped to marketplace-factory meta-tooling,
not generic target-repo documentation (see ADR-0012). Moves the agentsmd
research corpus from plugins/kyberforge to plugins/core to match.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

plugins/core/docs/research/docs/agentsmd/configuration.md

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+---
+topic: configuration
+source_keys:
+  - agents-md-official
+  - context7-websites-agents-md
+---
+
+## General Setup
+
+No installation is required. Create a file named `AGENTS.md` at the root of the repository. Most agents that support the standard read it automatically without any configuration.
+
+## Tool-Specific Configuration
+
+Some tools require an explicit opt-in to read AGENTS.md:
+
+**Aider** — add to `.aider.conf.yml`:
+```yaml
+read: AGENTS.md
+```
+
+**Gemini CLI** — add to `.gemini/settings.json`:
+```json
+{
+  "context": {
+    "fileName": "AGENTS.md"
+  }
+}
+```
+
+For all other tools in the compatibility list (GitHub Copilot, Cursor, Codex, Claude Code, etc.), AGENTS.md is read automatically when present at the repository root or in the nearest parent directory.
+
+## Conflict Resolution
+
+- Nearest file wins: the AGENTS.md closest to the file being edited takes precedence over files higher in the directory tree.
+- User prompt wins over all: explicit instructions given in the chat interface override any AGENTS.md rule.
+- No merge across files: only the nearest file applies; inner files do not inherit from outer ones unless the agent explicitly implements that behavior.

plugins/core/docs/research/docs/agentsmd/examples.md

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+---
+topic: examples
+source_keys:
+  - agents-md-official
+  - context7-websites-agents-md
+  - context7-agentsmd-agents-md
+---
+
+## Minimal Project Example
+
+A practical AGENTS.md covering setup, code style, testing, and PR conventions for a pnpm monorepo:
+
+```markdown
+# AGENTS.md
+
+## Setup commands
+- Install deps: `pnpm install`
+- Start dev server: `pnpm dev`
+- Run tests: `pnpm test`
+
+## Code style
+- TypeScript strict mode
+- Single quotes, no semicolons
+- Use functional patterns where possible
+
+## Dev environment tips
+- Use `pnpm dlx turbo run where <project_name>` to jump to a package instead of scanning with `ls`.
+- Run `pnpm install --filter <project_name>` to add the package to your workspace so Vite, ESLint, and TypeScript can see it.
+- Check the `name` field inside each package's `package.json` to confirm the right name.
+
+## Testing instructions
+- Find the CI plan in the `.github/workflows` folder.
+- Run `pnpm turbo run test --filter <project_name>` to run every check defined for that package.
+- From the package root you can just call `pnpm test`. The commit should pass all tests before you merge.
+- Fix any test or type errors until the whole suite is green.
+- Add or update tests for the code you change, even if nobody asked.
+
+## PR instructions
+- Title format: [<project_name>] <Title>
+- Always run `pnpm lint` and `pnpm test` before committing.
+```
+
+## Monorepo Nested Structure
+
+Place AGENTS.md files at each scope level. Agents read the nearest file automatically:
+
+```
+my-monorepo/
+├── AGENTS.md              # Root-level: applies to the whole repo
+├── packages/
+│   ├── api/
+│   │   └── AGENTS.md      # API-specific instructions; overrides root for this package
+│   ├── web/
+│   │   └── AGENTS.md      # Web app-specific instructions
+│   └── shared/
+│       └── AGENTS.md      # Shared library instructions
+```
+
+Each sub-AGENTS.md can focus on the specifics of that package (framework, test runner, build tool) without repeating root-level conventions.
+
+## What Agents Do with AGENTS.md
+
+Agents actively use the file — they attempt to run listed test commands and fix failures before completing a task. Treat the instructions as live directives, not documentation. Keep the file updated as tooling and conventions change.

plugins/core/docs/research/docs/agentsmd/overview.md

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+---
+topic: overview
+source_keys:
+  - agents-md-official
+  - context7-websites-agents-md
+  - context7-agentsmd-agents-md
+---
+
+## What AGENTS.md Is
+
+AGENTS.md is an open format that serves as a dedicated README for AI coding agents — a single, predictable file where developers place context and instructions that help agents work effectively on a project. It is now stewarded by the Agentic AI Foundation under the Linux Foundation, having emerged from collaboration between OpenAI Codex, Amp, Jules (Google), Cursor, and Factory.
+
+The format intentionally complements rather than replaces README.md. README stays focused on human contributors; AGENTS.md carries the agent-specific detail — build steps, test commands, conventions, security gotchas — that would clutter a README or is irrelevant to humans.
+
+Over 60,000 open-source projects use it.
+
+## Format
+
+AGENTS.md is plain Markdown placed at the root of a repository. There are no required fields, no schema, and no special syntax — agents parse the text. Developers use any headings appropriate to their project.
+
+Common sections include:
+- Project overview
+- Build and test commands
+- Code style guidelines
+- Testing instructions
+- Security considerations
+- Commit message conventions
+- Pull request guidelines
+- Deployment steps
+
+## Precedence Rules
+
+When multiple AGENTS.md files exist (common in monorepos), the file closest to the edited file in the directory tree takes precedence. Explicit user chat prompts override all AGENTS.md instructions.
+
+## Monorepo Support
+
+Place additional AGENTS.md files inside individual packages or subdirectories. Agents automatically read the nearest file, so subprojects can carry tailored instructions that supplement or override the root-level file. OpenAI's main repository contains 88 AGENTS.md files as an example of this pattern.
+
+## Cross-Tool Compatibility
+
+A single AGENTS.md works across the majority of AI coding tools. Confirmed compatible agents include: GitHub Copilot, VS Code AI, Cursor, Aider, Devin (Cognition), Windsurf (Cognition), OpenAI Codex, Google Jules, Gemini CLI, Zed, RooCode, Kilo Code, Warp, opencode, Amp, Factory, Augment Code, Junie (JetBrains), Semgrep, goose, Phoenix, Ona, UiPath Autopilot & Coded Agents, and Claude Code (Anthropic). The standard is designed to be vendor-neutral.

plugins/core/docs/research/docs/agentsmd/sources.md

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+# Sources
+
+## agents-md-official
+
+- **URL:** https://agents.md/
+- **Description:** Official agents.md website — overview, how-to guide, supported tools list, sample file, FAQ, and tool configuration snippets
+- **Contributing files:** overview.md, configuration.md, examples.md
+- **Status:** `extracted`
+
+## context7-websites-agents-md
+
+- **URL:** context7:/websites/agents_md
+- **Description:** Context7 index of the official agents.md website (High source reputation, benchmark score 93.78) — overview, governance, cross-tool compatibility, configuration examples, FAQ
+- **Contributing files:** overview.md, configuration.md, examples.md
+- **Status:** `extracted`
+
+## context7-agentsmd-agents-md
+
+- **URL:** context7:/agentsmd/agents.md
+- **Description:** Context7 index of the agentsmd/agents.md repository (Medium source reputation, 26 code snippets) — format spec, nested monorepo patterns, file structure examples
+- **Contributing files:** overview.md, examples.md
+- **Status:** `extracted`
+
+## agents-md-llms-txt
+
+- **URL:** https://agents.md/llms.txt
+- **Description:** Attempted fetch of llms.txt for machine-readable spec
+- **Contributing files:** (none)
+- **Status:** `no content extracted` — HTTP 404