feat(verify): add HTML embed path and extract parallel-generation rules

[bensonwong]

Summary

• New: HTML annotation path — when the user's claim source is a static HTML file they want to preserve, agents now annotate it directly instead of generating a new report. Uses data-cite="N" attributes on any HTML element and appends <<<CITATION_DATA>>> as raw text after </html>; parseCitationData() strips it before output so it never renders in the browser. Runs verify --html to inject the CDN runtime while preserving original structure and styling.
• New §2 triage row — routes "embed citations into static HTML" to the HTML annotation path; narrows the existing "Existing verified HTML" row to clarify it covers only prior CLI output (already has data-citation-key attributes).
• §4 --html note updated — now covers both entry points: embed-into case (.deepcitation/{draft}-body.html) and re-verify of prior CLI output.
• Parallel generation extracted — the full parallel-agent pipeline (evidence tagging, split/overlap math, merge failure recovery) moves to rules/parallel-generation.md. SKILL.md defers to it for 100+ page / 3+ file scenarios; single-topic and sub-100-page cases stay inline.
• AGENTS.md guidance router — new entry pointing to rules/parallel-generation.md.
• Cleanup — removed cloud-sandbox probe block, proxy invariants, tool alternatives enumeration, and results summary emoji line from SKILL.md (each covered by their respective rules files).

Test plan

• Read SKILL.md §1–§4 end-to-end: confirm read-only, verify/markdown, and verify/html-embed are each clearly differentiated in Orient and Triage
• Trace the HTML embed path: §2 triage → §3 HTML annotation path → data-cite wrapping → <<<CITATION_DATA>>> after </html> → §4 verify --html .deepcitation/{draft}-body.html
• Confirm rules/parallel-generation.md exists and contains the full pipeline (evidence tagging, split math, merge failure recovery)
• Confirm AGENTS.md guidance router lists parallel-generation.md under the correct trigger keywords

[claude]

PR Review

Overall this is a well-structured refactor. Extracting the parallel pipeline into its own rules file and adding the HTML embed path are both good moves. A few issues worth addressing before merge.

---

Blocking / Correctness

Threshold mismatch: three inconsistent definitions of when to use parallel generation

• SKILL.md section heading: "100+ pages with 3+ files"
• parallel-generation.md (When to use): "100 or more pages AND the question spans 2 or more distinct topics"
• AGENTS.md guidance router: "100+ page documents" (no topic or file condition)

The original SKILL.md was internally consistent ("2+ distinct sections / 2+ top-level headings"). Pick one formulation and apply it in all three places.

No direct-read fallback rule silently gutted in the Hard rules section

Old text named the forbidden tools (Read, pdfplumber, urllib, web fetch, etc.) and explained why the rule exists: a hand-built report that mimics the verified format presents unverified text as verified.

New text collapses to: "If prepare/verify cannot complete, the deliverable is not producible."

This is the exact moment agents are most tempted to reach for an alternative tool. The explanation needs to live here — either restore it inline or add an explicit pointer to the file that carries the full rule.

---

Significant

Cloud-sandbox probe removed with no guaranteed load trigger

The original section warned: "false negatives are catastrophic because the agent loses awareness of the 45 s bash timeout, the __DC_ERROR__ protocol, and the no-fallback invariant."

The proactive probe (env | grep ..., whoami) is gone. cloud-sandbox-constraints.md now only appears in the AGENTS.md router under the keyword "cloud sandbox behavior" — an agent that doesn't already suspect it's in a sandbox will never load that file, which is the false-negative scenario the original text warned about. At minimum restore a one-liner in the Hard rules: "Before running any CLI command, probe for cloud-sandbox markers — see rules/cloud-sandbox-constraints.md."

Proxy invariant dropped from Invariants

"Never modify proxy environment variables on individual command runs" was listed in Invariants — the section that applies everywhere, sandbox or not — precisely because this failure mode appears outside sandboxes too. The rules file is on-demand only. Restoring this line to Invariants is one sentence and closes a real gap.

---

Minor / Polish

Triage row example text is awkward

Old: (e.g. index.html, draft.md) — New: (e.g. draft.md, or files that have made unfounded claims that need verification)

A file doesn't make claims. Consider: (e.g. draft.md, a report, or any document containing claims to check).

Results summary format dropped with no pointer

The verified/partial/not-found summary format was removed from the closing step. None of the linked rules files appear to own it. If it's intentionally retired, say so in the section; otherwise agents will invent inconsistent formats.

parseCitationData() is an internal function name in agent-facing docs

Fragile if the function is renamed. Rewrite as observable behavior: "The CLI strips everything from <<<CITATION_DATA>>> to <<<END_CITATION_DATA>>> before writing the output file, so this block never appears in the browser."

CLI version note (deepTextPromptPortion fallback) was removed

Fine if the minimum supported CLI now always emits deepTextPages — but worth a brief comment in the PR description so this is explicitly intentional rather than an accidental omission.