Add CLI commands for task management

[bborn]

Summary

• Add comprehensive CLI commands to manage tasks from the command line, enabling programmatic task management without the TUI
• Implements create, list, show, update, execute, close, and retry commands
• All commands support JSON output for programmatic use

New Commands

Command	Description	Example
task create <title>	Create a new task	task create "Fix bug" -x --priority high
task list	List tasks with filters	task list --status queued --json
task show <id>	Show task details	task show 42 --logs
task update <id>	Update task fields	task update 42 --title "New title"
task execute <id>	Queue for execution	task execute 42 (aliases: queue, run)
task close <id>	Mark as done	task close 42 (aliases: done, complete)
task retry <id>	Retry blocked task	task retry 42 -m "Try different approach"

Test plan

• All new CLI tests pass (go test ./cmd/task/...)
• Existing tests still pass
• Manual testing of each command
• Test JSON output parsing with jq

🤖 Generated with Claude Code