feat: Add bd repos multi-repo commands and fix bd ready for in_progress issues

- Add 'bd repos' command for multi-repository management (bd-123)
  - bd repos list: show all cached repositories
  - bd repos ready: aggregate ready work across repos
  - bd repos stats: combined statistics across repos
  - bd repos clear-cache: clear repository cache
  - Requires global daemon (bd daemon --global)

- Fix bd ready to show in_progress issues (bd-165)
  - bd ready now shows both 'open' and 'in_progress' issues with no blockers
  - Allows epics/tasks ready to close to appear in ready work
  - Critical P0 bug fix for workflow

- Apply code review improvements to repos implementation
  - Use strongly typed RPC responses (remove interface{})
  - Fix clear-cache lock handling (close connections outside lock)
  - Add error collection for per-repo failures
  - Add context timeouts (1-2s) to prevent hangs
  - Add lock strategy comments

- Update documentation (README.md, AGENTS.md)
- Add comprehensive tests for both features

Amp-Thread-ID: https://ampcode.com/threads/T-1de989a1-1890-492c-9847-a34144259e0f
Co-authored-by: Amp <amp@ampcode.com>

cmd/bd/ready.go

@@ -15,13 +15,13 @@ import (
 
 var readyCmd = &cobra.Command{
 	Use:   "ready",
-	Short: "Show ready work (no blockers)",
+	Short: "Show ready work (no blockers, open or in-progress)",
 	Run: func(cmd *cobra.Command, args []string) {
 		limit, _ := cmd.Flags().GetInt("limit")
 		assignee, _ := cmd.Flags().GetString("assignee")
 
 		filter := types.WorkFilter{
-			Status: types.StatusOpen,
+			// Leave Status empty to get both 'open' and 'in_progress' (bd-165)
 			Limit:  limit,
 		}
 		// Use Changed() to properly handle P0 (priority=0)