feat: Add bd search command for efficient text queries (#347)

Adds a new `bd search` command optimized for quick text searches,
addressing the issue where Claude using MCP bd list consumes 30k tokens.

Features:
- Searches across title, description, and ID with OR logic
- Default limit of 50 results (vs unlimited for bd list)
- Supports key filters: --status, --assignee, --type, --label
- Works in both daemon and direct modes
- Provides --json and --long output formats

Examples:
  bd search "performance" --status open
  bd search "database" --label backend --limit 10
  bd search "bd-5q"  # Search by partial ID

This provides a more efficient alternative to bd list when users
just want to find issues quickly without loading all results.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

commands/search.md

@@ -0,0 +1,89 @@
+---
+description: Search issues by text query
+argument-hint: <query> [--status] [--label] [--assignee]
+---
+
+Search issues across title, description, and ID with a simple text query.
+
+**Note:** The `search` command is optimized for quick text searches and uses less context than `list` when accessed via MCP. For advanced filtering options, use `bd list`.
+
+## Basic Usage
+
+```bash
+bd search "authentication bug"
+bd search login --status open
+bd search database --label backend
+bd search "bd-5q"  # Search by partial issue ID
+```
+
+## How It Works
+
+The search command finds issues where your query appears in **any** of:
+- Issue title
+- Issue description
+- Issue ID (supports partial matching)
+
+Unlike `bd list`, which requires you to specify which field to search, `bd search` automatically searches all text fields, making it faster and more intuitive for exploratory searches.
+
+## Filters
+
+- **--status, -s**: Filter by status (open, in_progress, blocked, closed)
+- **--assignee, -a**: Filter by assignee
+- **--type, -t**: Filter by type (bug, feature, task, epic, chore)
+- **--label, -l**: Filter by labels (must have ALL specified labels)
+- **--label-any**: Filter by labels (must have AT LEAST ONE)
+- **--limit, -n**: Limit number of results (default: 50)
+- **--long**: Show detailed multi-line output for each issue
+- **--json**: Output results in JSON format
+
+## Examples
+
+### Basic Search
+```bash
+# Find all issues mentioning "auth" or "authentication"
+bd search auth
+
+# Search for performance issues
+bd search performance --status open
+
+# Find database-related bugs
+bd search database --type bug
+```
+
+### Filtered Search
+```bash
+# Find open backend issues about login
+bd search login --status open --label backend
+
+# Search Alice's tasks for "refactor"
+bd search refactor --assignee alice --type task
+
+# Find recent bugs (limited to 10 results)
+bd search bug --status open --limit 10
+```
+
+### JSON Output
+```bash
+# Get JSON results for programmatic use
+bd search "api error" --json
+
+# Use with jq for advanced filtering
+bd search memory --json | jq '.[] | select(.priority <= 1)'
+```
+
+## Comparison with bd list
+
+| Command | Best For | Default Limit | Context Usage |
+|---------|----------|---------------|---------------|
+| `bd search` | Quick text searches, exploratory queries | 50 | Low (efficient for LLMs) |
+| `bd list` | Advanced filtering, precise queries | None | High (all results) |
+
+**When to use `bd search`:**
+- You want to find issues quickly by keyword
+- You're exploring the issue database
+- You're using an LLM/MCP and want to minimize context usage
+
+**When to use `bd list`:**
+- You need advanced filters (date ranges, priority ranges, etc.)
+- You want all results without a limit
+- You need special output formats (digraph, dot)