chore: drop the duplicated package descriptions from root apm.yml

Why: for a local-path marketplace entry, apm treats a root description: as
an override of the package's own apm.yml, reported only at verbose level,
so the "two copies stay identical" rule had no enforcement. Same fix as
2def060 made for version:.

Implementation Notes:
- All six root copies matched their package apm.yml before removal; the
  compiled marketplace.json descriptions are unchanged.
- apm-workflow references now scope the "omit it" advice to local-path
  entries: on a remote entry, version: is the semver range that selects
  the tag, and version: or ref: is required.

Impact: ADR-0021 amended; the package apm.yml is the single source.

ADR: 0021
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

apm.yml

@@ -75,31 +75,25 @@ marketplace:
 
   packages:
     - name: kyberforge
-      description: Skills and agents for creating, maintaining, and managing a Claude Code / Copilot CLI plugin marketplace.
       source: ./plugins/kyberforge
       category: Developer Tools
 
     - name: bin
-      description: Skills for everyday AI-assisted development work that is not tied to a single tool, forge or language, and has not yet been split into a focused plugin.
       source: ./plugins/bin
       category: Utilities
 
     - name: git
-      description: Skills and agents for working with a local Git clone over the git wire protocol, and for authoring and running the pre-commit hooks that guard it.
       source: ./plugins/git
       category: Version Control
 
     - name: gitea
-      description: Skills and agents for working with a Gitea forge through its HTTP API — the forge's own objects, as distinct from the local git clone.
       source: ./plugins/gitea
       category: Version Control
 
     - name: core
-      description: Skills for authoring and auditing a repo's AGENTS.md and the provider adapter files that defer to it.
       source: ./plugins/core
       category: Productivity
 
     - name: lint
-      description: Skills and agents for configuring and running linters.
       source: ./plugins/lint
       category: Developer Tools