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/references/deployment-modes.md

@@ -22,13 +22,14 @@ Agent definitions deploy at three scopes and behave differently at each. The sco
 
 When the same agent `name` appears at multiple scopes, **user scope wins over project scope wins over plugin scope** in Claude Code. In Copilot CLI, repo-level agents override enterprise and org-level; home-directory (user) agents override repo-level on name collision.
 
-## Plugin scope restrictions
+## Which fields exist where
 
-Plugin/APM agents (`.apm/agents/<name>.agent.md`) carry only the fields in the `apm-agent-allowlist` section of `agent-audit`'s `references/field-inventory.md`. That section is the authoritative list — `agent-audit`'s `validate.sh` reads it from there as data, and it changes — so consult it rather than any restatement of it. `apm compile` copies this frontmatter verbatim to both the Claude Code and Copilot CLI compile targets with no per-target integrator, so a harness-specific value is guaranteed wrong on at least one target (ADR-0016).
-
-**The rule is about a field's shape, not a fixed roster.** `tools` is an **allowlist** whose vocabulary differs per harness — Claude Code names its own tools, Copilot CLI uses aliases (`execute`/`read`/`edit`/`search`/`agent`/`web`) — so under verbatim copy one value is wrong on one target. It stays out. `disallowedTools` is a **denylist**, and denying by name has no such conflict: a name the other harness does not recognise denies nothing, so the worst case is that the fence is absent there, never that a capability is wrongly granted. That asymmetry is why the denylist is admitted where the allowlist is not (ADR-0016's 2026-08-14 amendment). Claude Code honours it for plugin subagents — `docs/research/docs/claude-code-plugins/agent-definition.md:99` names the three fields plugin agents silently ignore (`hooks`, `mcpServers`, `permissionMode`) and `disallowedTools` is not among them. It is a partial fence: it denies only the tools it names, not `Bash`, which a plugin-scope agent with no `tools` inherits — so state read-only intent in the body too.
-
-This makes the old "silently ignored at plugin scope" framing moot for the excluded fields. It's not that `hooks`, `mcpServers`, `permissionMode`, `tools`, `isolation`, `maxTurns`, `effort`, `memory`, `skills`, `color`, `initialPrompt`, or `background` are merely ignored at this scope — they are never written to the file at all. Copy the agent to `.claude/agents/` (project scope) or `~/.claude/agents/` (user scope) to use any of them.
+Field rules are per scope and live with the scope: `references/plugin-scope.md` for the single
+vendor-neutral file, `references/project-user-scope.md` for the Claude Code / Copilot pair. Read
+one, not both. The short version is that plugin/APM frontmatter is an allowlist read from
+`agent-audit`'s `references/field-inventory.md`, narrow because `apm compile` copies frontmatter
+verbatim to every target (ADR-0016), while project and user scope carry the full per-provider
+field sets.
 
 ## Scoped identifiers (Claude Code plugin agents only)