feat: bmalph import — import tasks from external sources

[LarsCowe]

Summary

Ralph has task source support in ralph/lib/task_sources.sh (GitHub Issues, beads, PRD extraction) but no bmalph CLI command exposes this functionality.

Proposed Solution

A bmalph import command that:

1. Detects available task sources (GitHub Issues, beads, local PRD)
2. Offers interactive selection when multiple sources are available
3. Converts selected tasks to @fix_plan.md format
4. Optionally appends to existing fix plan or replaces it

Subcommands / Options

• bmalph import github — Import from GitHub Issues (filtered by label)
• bmalph import prd — Extract tasks from a PRD document
• bmalph import beads — Import from beads
• --append — Add to existing fix plan instead of replacing
• --label <label> — GitHub Issues label filter (default: ralph-task)
• --dry-run — Preview imported tasks without writing

Value

Most valuable for users who skip BMAD planning and want to drive Ralph directly from GitHub Issues or other external task sources.

Additional Context

The underlying machinery exists in Ralph's task_sources.sh. This command would be a thin CLI wrapper that invokes those functions and formats the output.