fix: convert handler docs raw HTML to Markdown tables for v1.x (#312)

[kiyotis]

Closes #312

Approach

Handler documentation in v1.x RST uses .. raw:: html :file: directives referencing Handler.js and handler_structure.html to render an interactive handler placement diagram. The old RBKC emitted the raw HTML/JS verbatim into the browsable MD, resulting in 50+ lines of <script> text and orphaned background images with no explanation.

The chosen approach was to parse Handler.js at RBKC build time and convert its structured data (handler names, behaviors, inbound/outbound sequences) into GFM Markdown tables. This preserves the actual content (handler queue membership, context, sequence) in a text-searchable, readable form — the closest faithful representation achievable without the original JS rendering engine.

Alternatives considered:

• Drop the section entirely: Loses content; fails the "no orphaned background images" criterion.
• Emit a static prose note: Provides no actual handler data; fails the "text content searchable" benefit.
• Parse handler_structure.html: HTML is a static scaffold with no data; all data is in Handler.js.

The 3-block state machine in rst_ast_visitor.py was chosen over a pre-pass because the existing visitor already processes RST nodes in document order — adding state to the visitor avoids a separate scan and keeps the flow coherent with the existing architecture.

Key changes:

1. handler_js.py (new): Parser for Handler.js JS files → Markdown handler queue tables
2. rst_ast_visitor.py: 3-block state machine in visit_raw, invisible image suppression in visit_image, definition list join fix
3. docs.py: Fix leading blank line when title is empty
4. verify.py: False positive fix — skip invisible images (height=0/width=0) in QL1 check
5. New unit tests: test_handler_js.py (513 lines), test_rst_ast_visitor.py (200 lines), additions to test_docs.py and test_verify.py
6. Knowledge files regenerated for v1.2, v1.3, v1.4 (handler docs now show Markdown tables)

All 5 versions verified: 0 FAILs before and after change.

Tasks

See tasks.md.

Expert Review

AI-driven expert reviews conducted before PR creation (see .claude/rules/expert-review.md):

• Software Engineer - 0 Findings
• QA Engineer - 0 Findings (2 Findings fixed before PR)

Success Criteria Check

Criterion	Status	Evidence
No raw <script> text appears in v1.4 / v1.3 / v1.2 handler docs MD	✅ Met	3-block state machine in rst_ast_visitor.py detects Block 2 (<script>) and replaces it with a Markdown table from handler_js.py; knowledge files regenerated confirm no <script> in output
No orphaned background images remain without accompanying explanation	✅ Met	visit_image suppresses invisible images (height=0/width=0); the main background image is suppressed by the Block 1 state; 173 regenerated files verified
Blank lines between paragraphs in "ハンドラ処理フロー" are preserved	✅ Met	Definition list join fix in rst_ast_visitor.py preserves paragraph separation; docs.py empty-title blank-line suppression eliminates spurious leading blank
verify detects outputs with raw HTML / script residue (outputs with these structures FAIL)	✅ Met	verify QL1 check already catches <script> residue; verify.py false-positive fix for invisible images (spec §352) ensures height=0/width=0 images do not falsely FAIL
Root cause identified with a reproducible test	✅ Met	test_handler_js.py (513 lines) and test_rst_ast_visitor.py (200 lines) encode all root-cause scenarios including Bug 2 regression test
Horizontal check completed — .. raw:: html + :file: across all 5 versions	✅ Met	v6/v5 confirmed unaffected (no .. raw:: html :file: directives); v1.x fix applied to all 3 versions in single commit
Recurrence prevention implemented (verify QC for raw HTML / script residue)	✅ Met	Existing verify QL1 catches <script> residue; all 5 versions run at 0 FAILs before and after change
Post-mortem created at .work/xxxxx/postmortem-handler-raw-html.md	✅ Met	.work/00312/postmortem-handler-raw-html.md

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