docs: recurse complex problems to the fast path

[iteathen]

Summary

• make recursive decomposition part of the adaptive problem-solving cycle
• require large/complex work to be decomposed along real ownership/contract/lifecycle/dependency seams when useful
• reclassify each child independently and return simple, small, understood leaves to the normal fast path
• treat the decomposition as a dependency web when appropriate, not necessarily a tree
• keep parent-level integration, completeness, and original acceptance-condition qualification
• clarify that the extended cycle exists only for complex, large-scope, or materially uncertain work

Scope

Documentation/governance only. No runtime, schema, ABI, support, or compatibility claims change.

Validation

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