feat: v0.10.0 quieter Matrix, worktrees, usage pace, repo diffs, copy reply, turn timer, compact

- Matrix "needs you": ignore Claude's idle reminder (no red, no post); post
  only when no tab is in view, after 60 s, once per session per 10 min, and
  say what is asked. Closes #50
- devdesk new NAME PROJECT --worktree: own checkout on devdesk/NAME,
  cleaned up on end when clean/merged. Closes #44
- Usage meters: reset time, pace warning; Matrix ping past 90% when away.
  Closes #45
- Repo panel lists changed files; click opens the diff. Closes #46
- Copy Claude's last reply (--last-reply). Closes #47
- Turn timer in chip, title and cards. Closes #48
- Compact button at 80% context when idle. Closes #49

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WHRLCCdXYm41Qx5kNhehaP

libexec/devdesk-lib.sh

@@ -58,7 +58,9 @@ dd_load_env
 : "${DEVDESK_UPLOAD_MAX:=26214400}"
 : "${DEVDESK_PUBLIC_URL:=}"
 : "${DEVDESK_MATRIX_WEBHOOK_FILE:=/etc/devdesk/matrix-webhook}"
-: "${DEVDESK_MATRIX_DELAY:=30}"
+: "${DEVDESK_MATRIX_DELAY:=60}"
+: "${DEVDESK_MATRIX_QUIET:=600}"
+: "${DEVDESK_USAGE_WARN:=90}"
 : "${DEVDESK_PRESENCE_DIR:=/run/devdesk/presence}"
 
 DEVDESK_REGISTRY="$DEVDESK_STATE_DIR/registry.json"