cmdPhasePlanIndex had 3 mismatches with the canonical XML plan format
defined in templates/phase-prompt.md:
- files_modified: looked up fm['files-modified'] (hyphen) but plans use
files_modified (underscore). Now checks underscore first, hyphen fallback.
- objective: read from YAML frontmatter but plans put it in <objective>
XML tag. Now extracts first line from the tag, falls back to frontmatter.
- task_count: matched ## Task N markdown headings but plans use <task>
XML tags. Now counts XML tags first, markdown fallback.
All three fixes preserve backward compat with legacy markdown-style plans.
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
3a417522c9