docs(kyberforge): fix path drift and content gaps from apm conversion

The apm conversion (5e23250) moved skills/agents to plugins/<name>/.apm/
and deleted plugin-author/marketplace-author, but a review against issue
#90's Definition of Done found several stale pre-conversion references
left behind by straight git-mv's, plus one real content gap:

- ADR-0014 still documented the old flat vale-prefilter paths in 6
  places, despite ADR-0015 claiming it had been updated.
- ADR-0015 also overclaimed: it said ADR-0014 had both a skills/ and an
  agents/ path regex updated, but ADR-0014 never had an agents/ path
  regex to begin with (its one "agents" mention is a Vale glob-section
  identifier, not a filesystem path). Corrected the wording.
- CONTEXT.md's Skill glossary entry, its Vale-prefilter section, and its
  plugin-author/marketplace-author forward-pointer all still described
  the pre-conversion layout or a "pending issue #90" state that has since
  landed.
- LESSONS.md and two skill test READMEs pointed at skill-author/
  skill-audit/agent-author paths without the .apm/ segment.
- apm-workflow/references/marketplace.md cited plugin-author/SKILL.md's
  Gotchas for the Claude Code reserved plugin-name-prefix list, but that
  list was never actually carried into apm-workflow during the
  conversion despite ADR-0015 claiming it was. Recovered the list from
  git history and inlined it directly rather than leaving a dangling
  citation.
- agent-author/references/deployment-modes.md had an example
  contradicting its own stated .apm/agents/ convention two lines above.

Refs: #90

plugins/kyberforge/.apm/skills/agent-author/references/deployment-modes.md

@@ -33,7 +33,7 @@ This makes the old "silently ignored at plugin scope" framing moot. It's not tha
 Plugin agents in **subdirectories** get compound identifiers:
 
 ```
-plugins/my-plugin/agents/review/security.md  →  my-plugin:review:security
+plugins/my-plugin/.apm/agents/review/security.agent.md  →  my-plugin:review:security
 ```
 
 Users must invoke with `@agent-my-plugin:review:security`. **Keep agents flat in `agents/` to avoid this** — subdirectory nesting is rarely worth the UX cost.