feat(integrations): add /plan-to-beads Claude Code command

Add slash command that converts Claude Code plan files into beads
epics with tasks and dependencies.

Features:
- Parses plan structure (title, summary, phases)
- Creates epic + tasks from phases
- Sets up sequential dependencies
- Uses Task agent delegation for context efficiency

Complements existing bd prime hooks for session start/end.

integrations/claude-code/commands/plan-to-beads.md

@@ -0,0 +1,62 @@
+# Convert Plan to Beads Tasks
+
+## description:
+Convert a Claude Code plan file into beads epic + tasks for cross-session tracking.
+
+## Arguments
+$ARGUMENTS (optional - path to plan file, defaults to most recent in ~/.claude/plans/)
+
+---
+
+Use the **Task tool** with `subagent_type='general-purpose'` to convert the plan.
+
+## Agent Instructions
+
+The agent should:
+
+1. **Find the plan file**
+   - If argument provided, use that path
+   - Otherwise: `ls -t ~/.claude/plans/*.md | head -1`
+
+2. **Parse the plan structure**
+   - Title: First `# Plan:` or `#` heading
+   - Description: Content under `## Summary`
+   - Tasks: Each `### Phase N:` or `### N.` section
+   - File list: Include in epic description
+
+3. **Create the epic**
+   ```bash
+   bd create "[Plan Title]" -t epic -p 1 -d "[summary]. Files: N to modify." --json
+   ```
+
+4. **Create tasks from phases**
+   - Each phase becomes a task
+   - Use first paragraph of phase content as description
+   ```bash
+   bd create "[Phase title]" -t task -p 2 -d "[description]" --json
+   ```
+
+5. **Add sequential dependencies**
+   - Phases are sequential: `bd dep add <phase2> <phase1>`
+
+6. **Link tasks to epic**
+   - `bd dep add <epic> <task>` for each task
+
+7. **Return a concise summary** (not raw output):
+   ```
+   Created from: [filename]
+
+   Epic: [title] ([epic-id])
+     ├── [Phase 1] ([id]) - ready
+     ├── [Phase 2] ([id]) - blocked by [prev]
+     └── [Phase 3] ([id]) - blocked by [prev]
+
+   Total: [N] tasks
+   Run `bd ready` to start.
+   ```
+
+## Notes
+
+- Original plan file is preserved for reference
+- Task descriptions use first paragraph only (keeps them scannable)
+- Sequential phases get automatic dependencies