fix(loaders): handle self-referencing types to avoid infinite recursion

[Mxiansen]

Related TAPD: https://tapd.woa.com/tapd_fe/10161711/story/detail/1010161711126433671

Background

Some APIs (e.g. billing/CreateGatherRule, billing/CreateAllocationRule, billing/ModifyAllocationRule) declare self-referencing request types, typically AllocationRuleExpression.Children: list<AllocationRuleExpression>.

The current expansion logic in tccli/loaders.py (_get_param_info, _generate_param_skeleton, _get_unfold_param_info) walks the type graph without any cycle detection or depth bound, recursing forever and ending with RecursionError, which breaks:

• tccli <svc> <action> help
• tccli <svc> <action> --generate-cli-skeleton
• tccli <svc> <action> --cli-unfold-argument ...

优化内容

• _get_param_info: introduce path-level visited frozenset + max_depth=20 fallback; on cycle hit, the node degenerates to a placeholder leaf (members becomes the type-name string/list).
• _generate_param_skeleton: same protection; emits "RecursiveRef<TypeName>" placeholder so users know to pass the field as a whole JSON via --cli-input-json.
• _get_unfold_param_info / _recur_get_unfold_param_info: same protection; registers current path as a leaf when a cycle is hit.
• _filling_unfold_param_info: detects truncated leaves (members is a placeholder string/list rather than dict), marks them type=Object and appends a JSON-input hint to the document.
• visited is path-scoped (visited | {member} derives a new frozenset on each descent), so sibling fields sharing the same plain struct are not mistakenly truncated.

Compatibility

• Single-file change: tccli/loaders.py.
• For non-recursive APIs (the vast majority), output is byte-identical before and after this patch (verified against cvm/RunInstances, cvm/DescribeInstances, billing/DescribeBillSummary, etc.).

Internal MR: https://git.woa.com/tencentcloud-internal/tencentcloud-cli/merge_requests/18