Establish task-tailored CSE function and sequence quality checks

[ajhcs]

The CSE skills currently leave function naming, requested decomposition levels, and participant-exchange timing implicit. This change establishes proportionate guidance across the three independently invocable skills and adds opt-in documentary structure checks through cse.py check --view-profile.

A requested hierarchy now declares its level-0 root, levels, and parent links; missing requested levels/IDs, orphaned nodes, cycles, and duplicate identities cannot pass. Task profiles configure counts and coverage without universal breadth/depth requirements. Sequences declare native participants and ordered exchanges; modeled timing uses finite numeric ranges, units, and a basis, and becomes required only when the task profile says so. Justified profile exceptions remain visible. Action meaning, exchange usefulness, and engineering completeness explicitly require human assessment rather than a verb dictionary.

Existing unannotated SysML models and legacy JSON helpers retain their semantics. Native models remain authoritative; the new metadata establishes documentary structure, not native containment, behavior, or engineering acceptance. Read-only comparison against the unmerged foundation branch identified existing role/decomposition/source-diagram checks. When existing cseWorkflow metadata is present, the additive tree metadata must reconcile with its exact function identities and decomposition edges. This is bounded reconciliation, not full workflow/source validation. No renderer, visual-study files, or unpublished branch implementation is incorporated.

Validation:

• python3 -B scripts/check.py --require-sysml: all 203 tests across 14 suites passed without skips, including 29 new structural, negative, tailoring, CLI, native-parser, and workflow-reconciliation tests.
• Independent read-only review found no remaining actionable issues after fixes for invalid explicit profiles and conflicting documentary trees; reviewer also ran the 25 tests requiring no filesystem writes.
• git diff --check: clean. Examples and fixtures are entirely synthetic.
• GitHub CI passed on Python 3.10 and 3.12 for both the push run and PR run, all four jobs successful.

Integration into the separate unpublished seven-skill foundation branch is not claimed by this PR. No merge is requested.