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/import.md

@@ -0,0 +1,36 @@
+---
+description: Import issues from JSONL format
+argument-hint: [-i input-file]
+---
+
+Import issues from JSON Lines format (one JSON object per line).
+
+## Usage
+
+- **From stdin**: `bd import` (reads from stdin)
+- **From file**: `bd import -i issues.jsonl`
+- **Preview**: `bd import -i issues.jsonl --dry-run`
+- **Resolve collisions**: `bd import -i issues.jsonl --resolve-collisions`
+
+## Behavior
+
+- **Existing issues** (same ID): Updated with new data
+- **New issues**: Created
+- **Collisions** (same ID, different content): Detected and reported
+
+## Collision Handling
+
+When merging branches or pulling changes, ID collisions can occur:
+
+- **--dry-run**: Preview collisions without making changes
+- **--resolve-collisions**: Automatically remap colliding issues to new IDs
+- All text references and dependencies are automatically updated
+
+## Automatic Import
+
+The daemon automatically imports from `.beads/issues.jsonl` when it's newer than the database (e.g., after `git pull`). Manual import is rarely needed.
+
+## Options
+
+- **--skip-existing**: Skip updates to existing issues
+- **--strict**: Fail on dependency errors instead of warnings