Add --resolve and --resolve-file flags to plan update

Acceptance Criteria

• --resolve <text> flag appends a ## Resolution section before the closing rune tag
• --resolve-file <path> reads resolution body from a file
• Completed: <today's ISO date> is auto-prepended as the first line of the section
• Resolution section is inserted before {% /work %} or {% /bug %} closing tag
• If a ## Resolution section already exists, new content is appended with a --- separator
• --resolve can be combined with --status done in a single command
• --resolve can be used standalone (without changing status) for incremental updates
• --resolve is only allowed on work and bug rune types (error for spec/decision/milestone)
• Unit tests cover: new resolution, append to existing, combined with status change, standalone resolve, file input, type restriction

Approach

Extend UpdateOptions in runes/plan/src/commands/update.ts with resolve?: string and resolveFile?: string. After applying attribute and checkbox changes, if resolve content is provided, locate the closing rune tag and insert the formatted Resolution section. Parse --resolve and --resolve-file in the CLI plugin's argument handling.

References

• Work Item Resolution Summaries
• Lumina Per-Rune Redundant CSS Cleanup — scanner must understand resolution format (parallel, not blocking)

Resolution

Completed: 2026-03-30

Full implementation in runes/plan/src/commands/update.ts with 9 unit tests covering all acceptance criteria (new resolution, append to existing, combined with status change, standalone resolve, file input, type restriction). All criteria verified met.