feat(kyberforge): enforce the ADR-0020 context contract for skills and agents

Skill name+description pairs are preloaded into every session, costing
~6,200 tokens across 39 skills before any skill is invoked. The authoring
rules mandated that growth: skill-author:104 and description-quality.md:21
both required padding, while skill-author:102 (the deflating rule) had no
FAIL condition behind it.

Gates (blocking, no baseline file):
- description 250 chars SUGGESTION / 400 FAIL, measured on the folded
  YAML value
- body-only 600 words SUGGESTION / 900 FAIL, independent of the unchanged
  whole-file 2770-word / 500-line spec backstop
- every boundary-clause routing target must resolve to a real skill or
  agent; catches skill-improve, neuledge-context and gitea-labels
- agents take the description gates but deliberately no body gate; a test
  pins that absence

Vale: DescriptionOpener widened to ^This\b, new CompositionNote rule
banning architecture notes from descriptions. 10 hits, 0 false positives.

Kyberforge's own four skills retrofitted: descriptions 3,364 -> 938 chars
(-72%), bodies 8,306 -> 2,487 words (-70%), all via the apm-workflow
dispatch pattern. Fixes the skill-improve dangling route and the
agent-author misroute to manual review.

Also fixes a pre-existing false positive where any line-initial 'read '
was flagged as interactive input, which had already caused two scripts to
be rewritten around it.

Refs: ADR-0020

plugins/kyberforge/skills/agent-author/assets/templates/copilot.agent.md.template

@@ -12,10 +12,16 @@
 name: AGENT_NAME
 <!-- Required. Kebab-case identifier. Home-directory version wins on name collision. -->
 
-description: FILL IN: Action-first description of what this agent does and when to invoke it.
-<!-- Required. Used by the runtime for automatic agent selection — quality matters.
-     Start with a verb: "Reviews...", "Analyzes...", "Generates..."
-     Example: "Reviews pull request diffs for security issues." -->
+description: FILL IN: Use when <trigger>. <One capability clause.> Not <thing> -> <name>.
+<!-- Required. Used by the runtime for automatic agent selection, and preloaded into
+     every session whether or not this agent is ever used. Three parts, nothing else:
+     a trigger clause opening "Use when", at most one capability clause, and a
+     boundary clause naming a real sibling skill or agent.
+     250 characters is the target, 400 the hard ceiling (ADR-0020).
+     Do not open with an action verb ("Reviews...", "Analyzes...") — that rule was deleted.
+     Keep it identical in wording to the Claude Code half of the pair.
+     Example: "Use when a diff needs checking for injected credentials before it
+     merges. Not general code review -> code-reviewer." -->
 
 <!-- tools: ["read", "search", "edit"]
      Optional. Array of tool names. Omit = all available tools. [] = no tools.
@@ -46,6 +52,11 @@ FILL IN: System prompt body. Should match the Claude Code version — the agent'
 
 You are a FILL IN: role description. When invoked, FILL IN: primary action.
 
+<!-- Delegate, don't restate. If an installed skill already owns a procedure this agent
+     needs, name it ("invoke `git-commits`") instead of transcribing it — a body that
+     restates a procedure an invocable skill owns is an agent-audit FAIL. One job per
+     agent. Delete this comment before shipping. -->
+
 ## Inputs
 
 FILL IN: What inputs does this agent expect? (files, context, parameters)