docs(claude): move single-scope guidance out of the root CLAUDE.md

[rodrigorjsf]

What this changes

Documentation and agent guidance only. No source, test logic or behavior changes.

The root CLAUDE.md loads in every session and had grown to 277 lines against a 200-line limit.
About a third of its Applied Learning bullets apply to one file pattern each. This moves them to
path-scoped rules, which load only when a matching file is touched. The root is now 186 lines.

Where things went

From the root	To	Loads when
6 snapshot and fixture bullets, plus the 3 corpus-count bullets as one line	new .claude/rules/behavior-gate.md	tests/behavior/**, tests/fixtures/**, pattern_defaults.py
25 vocabulary-guard, tree-sitter and detection bullets	new .claude/rules/framework-parsers.md	the three framework packages, framework.py, framework_*.py, the vocabulary guard tests
5 CLI and fake traps	.claude/rules/tests.md	tests/**/*.py
Spec execution workflow (27 lines)	new docs/agents/spec-workflow.md, with a pointer under Agent skills	read on demand
The drift schedule's two human steps	.claude/skills/upstream-sync/SKILL.md § 1	when the skill runs

Also in the root:

• Deleted, because a rule already says it: the fingerprint invariant and the discovered analyzer
  registry (analyzers.md), the meta stage's rewritten fields and the per-skill baseline
  (suppression.md).
• Merged near-duplicates: gh body edits (3 → 1), CRLF noise (2 → 1), Ticket PR checks (2 → 1),
  mutation testing (2 → 1).
• Code search shrinks to what the maintainer's global instructions do not already say.

Every original bullet is either present verbatim in the root or a rule, or is one of the merges and
deletions listed here. I checked that by comparing the old bullet list against the new files.

Two corrections

• A wrong bullet. "Renaming a vocabulary constant: … no test covers them" was false.
  contrib/vocabulary_sweep/tests/test_readers.py covers both role maps; it sits outside
  make test, which is probably how the bullet came to say otherwise.
• The squashed-sync repair (second commit). The sync skill and a bullet gave the repair as
  git merge -s ours upstream/main. That is only right while upstream has not moved. Once it has,
  the merge records commits nobody integrated as already merged, and the next sync skips them with
  no conflict to show it. The command now names the commit the sync merged, and the section says how
  the repair lands. PR merge: sync with NVIDIA/SkillSpector 2.12.0 #142 was squashed despite the warning in its body, so this was needed again.

Not changed, on purpose

• "Squash-merge Ticket PRs; DCO checks every merge commit inside the PR range." ci.yml appears
  to exempt a multi-parent merge whose committer is noreply@github.com, which would make this
  bullet imprecise. I have not measured it, so it stays as it is.
• .claude/rules/license-compliance.md is 156 lines and loads on every .py and .md. It is
  the compliance rule; I did not trim it.
• .gitattributes eol=lf would retire the CRLF bullets, but it renormalizes the tree of a fork
  that still merges upstream.

Verification

• tests/unit/test_upstream_drift_workflow.py, which reads the sync skill: 18 passed.
• Every path the moved text points to exists.
• Total line count across the touched files went up by a few lines (rule frontmatter and intros);
  always-loaded content went down by 91.