Add breadcrumbs to CLI responses for contextual next actions

[robzolkos]

Summary

• Add breadcrumbs feature to CLI responses - contextual "what can I do next?" suggestions
• Designed for AI agents to discover workflows without knowing the full CLI
• Also helpful for human users to learn available commands contextually

Changes

• Add Breadcrumb type with action, cmd, and description fields
• Add breadcrumbs array to Response struct (omitted when empty)
• Add helper functions: NewBreadcrumb(), SuccessWithBreadcrumbs(), SuccessWithPaginationAndBreadcrumbs()
• Add breadcrumbs to all commands (card, board, column, comment, step, reaction, user, tag, notification, search, auth, identity)
• Dynamic values (card numbers, board IDs, etc.) are interpolated into command suggestions
• Add unit tests for breadcrumb functionality
• Document breadcrumbs in README

Example

fizzy card show 42 | jq '.breadcrumbs'

[
  {"action": "comment", "cmd": "fizzy comment create --card 42 --body \"text\"", "description": "Add comment"},
  {"action": "triage", "cmd": "fizzy card column 42 --column <column_id>", "description": "Move to column"},
  {"action": "close", "cmd": "fizzy card close 42", "description": "Close card"},
  {"action": "assign", "cmd": "fizzy card assign 42 --user <user_id>", "description": "Assign user"}
]

Test plan

• Unit tests pass (go test ./...)
• E2E tested with live API - verified breadcrumbs present in responses
• E2E validated that breadcrumb command suggestions actually work when executed
• Tested card, board, column, comment, step, reaction, user, tag, notification, search, auth commands