docs(#54): F-4 legacy annotation + F-5 fixture convention -- AUDIT-01 housekeeping

INTEGRATION-AUDIT-01 (#50) §10.4 / §10.5 housekeeping carry-over.

F-4: annotate 14 remaining legacy Phase R'/Q sample-text hits across 10
src/ files with inline marker `# [legacy Phase R'/Q example -- INTEGRATION-AUDIT-01 §10.4]`.
Comment-only. No string-literal / regex / sample dict value mutated.
fit_verifier.py L612 marker keeps Phase Z partial-live import graph
(FitAnalysis / RoleFit / redistribute / salvage) byte-precise.

F-5: docs-only addendum -- §10.5.1 in INTEGRATION-AUDIT-01-REPORT.md +
tests/CLAUDE.md fixture convention note. No root tests/fixtures/ dir
created; existing tests/phase_z2/fixtures/ convention preserved. Documents
test-only sample-reference allowance vs src/** runtime prohibition.

Out of scope: Phase Z source 11 hits (phase_z2_content_extractor /
failure_router / mapper / retry), production behavior change, #19 work.

Verified: pytest -q tests/phase_z2/ = 157 PASS. git diff +210/-0
(35 src/docs lines + 175 new tests/CLAUDE.md). No behavioral delta.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/block_assembler_b2.py

@@ -8,6 +8,7 @@
 - 블록 CSS의 글씨 크기를 font_hierarchy에 맞게 조정 (프로세스 내 조정)
 - 콘텐츠는 PipelineContext에서 가져옴 (하드코딩 아님)
 - 블록은 콘텐츠에 맞게 재구성 (items 수 동적)
+  [legacy Phase R'/Q example — INTEGRATION-AUDIT-01 §10.4]
 """
 from __future__ import annotations