feat(integrations): add kernel Stripe catalog provider

[snowmead]

Summary

• Adds the kernel Stripe Projects catalog integration family as CatalogResource adapter(s).
• Follows docs/ADDING-A-PROVIDER.md and docs/PROVIDER-WAVES.md.
• Includes gap test + hermetic provision test. OUTPUT_FIELDS provisional until mise run discover.

Test plan

• Gap + hermetic tests in module
• Live mise run discover when provider is linked
• Merge after resolving additive registry.rs conflict with other family PRs

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Note

Low Risk
Standard additive catalog adapter and shared config helpers; no auth or lifecycle behavior changes beyond new provider registration.

Overview
Adds the KERNEL Stripe Projects catalog family for kernel/project, exposing ${integrations.*.api_key} via a managed CatalogResource with required name, registry wiring, and catalog-gap plus hermetic provision tests (provisional OUTPUT_FIELDS until discover).

Also extends stackless-provider-sdk with optional/required integer and boolean config helpers for richer catalog schemas, documents Phase 1 wave landing in PROVIDER-WAVES.md / DECISIONS.md, and adds generate_catalog_integrations.py to scaffold future deployables without rewriting registry rows.

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