docs(kyberforge): narrow issue #89 scope, migrate CC platform facts to apm-workflow

A grill-me session determined plugin-author/marketplace-author are fully
superseded by the landed apm-install/apm-workflow/apm-orchestrate artifacts
and will be deleted (not adapted) under issue #90, narrowing issue #89 to
skill-author/agent-author only; forge stays untouched. ADR-0015 is amended
to record this correction plus a three-way content-migration audit.

Claude Code platform-constraint facts that lived only in
plugin-author/marketplace-author (reserved name prefixes, the ADR-0010
agents/ stray-.md validator gotcha, claude plugin validate as a terminal
check, and a removal/re-pack confirm-before-proceeding note) remain true
post-conversion and are migrated into apm-workflow's reference docs via
kyberforge:skill-author, which also updated the skill's README and
sources.md provenance records. Dual-manifest-specific conventions (ADR-0006
parity, CC/Copilot field-placement split) do not carry forward since they
no longer apply.

ADR: 0015

plugins/kyberforge/skills/apm-workflow/references/audit.md

@@ -2,6 +2,8 @@
 topic: audit
 source_keys:
   - context7-microsoft-apm
+  - context7-websites-code-claude
+  - claude-code-plugins-docs
 ---
 
 ## `apm audit`
@@ -47,3 +49,7 @@ jobs:
 ## Frozen installs
 
 `apm install --frozen` fails instead of silently re-resolving if the lockfile is out of date — the CI equivalent of `npm ci` vs `npm install`. Use in any CI job that must not be allowed to drift the lockfile.
+
+## Claude Code validation is a separate terminal check
+
+For packages compiling to the `claude` target, also run `claude plugin validate [--strict]` against the compiled output as a terminal check. `apm audit`/`apm audit --ci` do not check Claude Code-marketplace-specific schema rules (reserved prefixes, the `agents/` stray-file behavior — see `references/compile.md` — etc.), so they don't substitute for it.

plugins/kyberforge/skills/apm-workflow/references/compile.md

@@ -42,3 +42,7 @@ apm run <script> [--param key=value]
 ```
 
 Executes a named script defined under `scripts:` in `apm.yml`, with `--param` substituting values into the script's parameters.
+
+## Gotchas
+
+- `claude plugin validate --strict` auto-scans every `.md` file directly under a compiled plugin's `agents/` directory and treats it as an agent definition requiring frontmatter, independent of any manifest declaration (this repo's own empirically-tested finding — see ADR-0010). A non-agent `.md` file (notes, provenance record, README) that ends up under `.apm/agents/` in the source tree will still fail validation once compiled to the `claude` target. Keep such files outside `.apm/agents/` (e.g. at the package root), regardless of what `apm.yml` declares.

plugins/kyberforge/skills/apm-workflow/references/marketplace.md

@@ -2,6 +2,8 @@
 topic: marketplace
 source_keys:
   - context7-microsoft-apm
+  - context7-websites-code-claude
+  - claude-code-plugins-docs
 ---
 
 ## Building a marketplace from a producer repo
@@ -60,3 +62,8 @@ Without this block, the default versioning strategy ties every listed package to
 - **Local packages, no distribution needed yet** — local-path dependencies in `apm.yml` (`./packages/my-shared-skills`); no marketplace or registry involved.
 - **Internal catalog, still git-based, no server** — `apm marketplace add` against a local path, bare repo, `file://` URI, or a plain git host.
 - **Package-level hosting at scale / access control** — registries (Artifactory-style REST endpoint); more infrastructure, only worth it once package count or access-control needs outgrow git-based discovery.
+
+## Gotchas
+
+- A package/plugin `name` compiling to the `claude` target must avoid Claude Code's reserved prefixes — `anthropic-*`, `claude-*`, `agent-skills`, `official-claude-plugins` — otherwise the compiled `.claude-plugin/marketplace.json` is rejected by Claude Code's validator. This is a Claude Code platform constraint, independent of how the manifest gets authored.
+- Removing a package from `marketplace.packages[]` in `apm.yml` and re-packing changes the public/consumed catalog. Whoever/whatever is driving this skill (human or agent) should confirm before proceeding, the same way `apm publish` is treated — see `apm-orchestrate.md`'s "Hard rules" section for the existing precedent on `publish`.

plugins/kyberforge/skills/apm-workflow/references/sources.md

@@ -7,3 +7,27 @@
 - **Research doc:** plugins/kyberforge/docs/research/docs/microsoft-apm/sources.md
 - **Contributing files:** SKILL.md, references/configure.md, references/install.md, references/marketplace.md, references/compile.md, references/audit.md
 - **Status:** `extracted`
+
+## context7-websites-code-claude
+
+- **URL:** context7:/websites/code_claude
+- **Description:** Official Claude Code documentation site indexed by Context7 — marketplace manifest schema (reserved name prefixes), `claude plugin validate` command behavior. Claude Code platform facts that hold true independent of how the compiled manifest is authored (APM or hand-authored).
+- **Research doc:** plugins/kyberforge/docs/research/docs/claude-code-plugins/sources.md
+- **Contributing files:** references/marketplace.md, references/audit.md
+- **Status:** `extracted`
+
+## claude-code-plugins-docs
+
+- **URL:** https://code.claude.com/docs/en/plugins
+- **Description:** Official Claude Code plugin authoring guide — marketplace submission constraints (reserved name prefixes), `claude plugin validate` behavior and its scope relative to other CI checks.
+- **Research doc:** plugins/kyberforge/docs/research/docs/claude-code-plugins/sources.md
+- **Contributing files:** references/marketplace.md, references/audit.md
+- **Status:** `extracted`
+
+## claude-code-subagents-docs
+
+- **URL:** https://code.claude.com/docs/en/sub-agents
+- **Description:** Official Claude Code subagent reference — definition format, all frontmatter fields, scope priority, built-in agents, CLI flags, environment variables, known limitations
+- **Research doc:** plugins/kyberforge/docs/research/docs/claude-code-plugins/sources.md
+- **Contributing files:** (none)
+- **Status:** `referenced`