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-audit/references/scope-project-user.md

@@ -0,0 +1,59 @@
+---
+source_keys:
+  - context7-websites-code-claude
+  - claude-code-subagents-docs
+  - context7-github-en-copilot
+  - github-custom-agents-configuration
+---
+
+# Project and User Scope Contract
+
+Read this when the agent file is not under `.apm/agents/` — a Claude Code `.md` and Copilot CLI
+`.agent.md` **pair**, at project scope (`<repo>/.claude/agents/` and `<repo>/.github/agents/`) or
+user scope (`~/.claude/agents/` and `~/.copilot/agents/`). `validate.sh` derives the counterpart
+from whichever half it was handed; audit both.
+
+## The pair is a house convention
+
+Neither platform requires a counterpart file. The pair is a kyberforge convention (ADR-0005), so a
+missing counterpart is a FAIL against **this repo's** convention and must be labelled that way in
+the finding, not presented as a platform spec failure.
+
+## Dimension routing
+
+`validate.sh` findings land as follows at these scopes:
+
+| Finding | Dimension |
+|---|---|
+| a Claude-Code-only field in the Copilot file, a Copilot-only field in the CC file, a tool the runtime withholds from subagents, body over the 30,000-character Copilot limit | Provider safety |
+| counterpart file not found | Pair consistency |
+| everything else — missing or malformed field, name format, empty body, absent frontmatter, description length | Structure |
+
+The two field lists are the `claude-code-only-fields` and `copilot-only-fields` sections of
+`references/field-inventory.md`. Read them from there rather than from memory; `validate.sh` parses
+those same sections, so any restatement is a copy that can disagree with the check (ADR-0009).
+
+## Field and naming rules that differ by provider
+
+- `name` must match the filename stem in a **Copilot CLI** `.agent.md`. Claude Code imposes no such
+  rule, so a CC file whose `name` differs from its filename is not a finding.
+- A Copilot **cloud/IDE** agent — one under `.github/copilot/agents/` — may omit `name` entirely.
+  If it carries one, it still has to be kebab-case.
+- `Use proactively` is meaningful in a CC description and steers the runtime to offer the agent
+  unprompted. In a Copilot description it does nothing; `KyberforgeCopilot.ProactivePhrase` flags
+  it. The Copilot equivalent is `disable-model-invocation` / `user-invocable`, which changes the
+  description contract entirely — see `references/description-quality.md`, Step 0.
+
+## Pair consistency
+
+Check that:
+
+- Both files exist.
+- Both system prompt bodies are non-empty (`validate.sh` covers this; do it by hand only when the
+  script could not run).
+- The two files describe the **same job**. Divergent capability claims across the pair mean one
+  half was edited and the other was not, which is the defect this dimension exists to catch.
+- Descriptions may legitimately differ in *shape* when the Copilot half is hand-invoked — that is
+  the Step 0 case in `references/description-quality.md`, not a pair-consistency finding.
+
+Keep `pair-consistency` in the Step 4 coverage line at these scopes.