Add command documentation and improve daemon UX

- Added human-readable uptime formatting (51m 59s vs 3119.4 seconds)
- Fixed daemon stop race condition with SIGKILL
- Added markdown docs for 19 commands: blocked, comments, compact, daemon,
  delete, dep, epic, export, import, label, list, quickstart, rename-prefix,
  renumber, reopen, repos, restore, stale, sync
- Closed: bd-159, bd-152, bd-168
- Deleted test issues: bd-144, bd-145

Amp-Thread-ID: https://ampcode.com/threads/T-9f7c3fed-62de-4bcd-a059-8c1b77cdb841
Co-authored-by: Amp <amp@ampcode.com>

commands/comments.md

@@ -0,0 +1,28 @@
+---
+description: View or manage comments on an issue
+argument-hint: [issue-id]
+---
+
+View or add comments to a beads issue.
+
+## View Comments
+
+To view all comments on an issue:
+- $1: Issue ID (e.g., bd-123)
+
+Use the beads CLI `bd comments <issue-id>` to list all comments. Show them to the user with timestamps and authors.
+
+## Add Comment
+
+To add a comment:
+- $1: "add"
+- $2: Issue ID
+- $3: Comment text (or use -f flag for file input)
+
+Use `bd comments add <issue-id> "comment text"` to add a comment. Confirm the comment was added successfully.
+
+Comments are useful for:
+- Progress updates during work
+- Design notes or technical decisions
+- Links to related resources
+- Questions or blockers