Add unreachable reference checkpoint to encode-policy-v2

[hua7450]

Summary

Adds a user checkpoint (Step 0E) to the /encode-policy-v2 command that surfaces references the document-collector could not automatically fetch (403, redirect, timeout). The user can then manually download and provide these files before the consolidation phase begins.

Motivation

During NH CCAP implementation, the document-collector found URLs for the official rate schedule (BCDHSC Form 2533) and cost share table (Form 2532/SR 24-08) but couldn't fetch them — NH DHHS returns 403 for automated requests while working fine in a browser. The agents fell back on the CCDF State Plan and Cornell LII, which had incomplete/outdated data:

• 24 of 45 rate values were wrong — HT/PT rates assumed FT/2 and FT/4, but actual ratios are ~77.4% and ~38.7%
• Cost share structure was only partially captured from the State Plan text
• Exempt center rules (school-age base rate, 72-month age guard) were missing

All of this was only discovered after the user manually downloaded Form 2533 and compared values.

Changes

1. Step 0E added after document-collector completes (Phase 0D) and before consolidation (Phase 1)
2. Document-collector prompt updated to report failed fetches in the research summary
3. User presented with AskUserQuestion listing unreachable URLs with options to download/skip/investigate
4. If user provides files, they are processed (text extraction + screenshots) and appended to working_references.md before consolidation

Common blocked sources (by state agency)

Agency	Blocked Content
NH DHHS	Rate schedules (Form 2533), cost share tables (Form 2532), SR announcements, policy manual
Many .gov sites	Provider enrollment pages, sliding fee schedules, operational forms