feat(monitors): add public folder management APIs

[UlricQin]

Add typed SDK support for monitor folder health, creation, updates, moves, and deletion. Preserve RuleFolders.List as a compatibility alias after generation introduces ReadList.

The vendored bilingual OpenAPI contracts document explicit zero when moving to the root, replacement semantics for note/team updates, and 409 FolderNotEmpty on deletion.

Validation:

• go test ./... passed, including App Key request coverage and an explicit dest_parent_id: 0 wire assertion.
• Regenerated services, models, and round-trip coverage from the updated specification.

Release coordination: the corresponding fc-pgy routes must accept App Keys before these methods work against that environment. Publish the SDK before releasing the CLI folder commands.

Related PRs:

• Gateway: https://github.com/flashcatcloud/fc-pgy/pull/1273
• SDK: feat(monitors): add public folder management APIs #102
• CLI: feat(monitors): add folder management commands flashduty-cli#232
• API documentation: docs(monitors): document public folder management APIs flashduty-docs#1058