feat(integrations): add parallel Stripe catalog provider

[snowmead]

Summary

• Adds the parallel 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
Additive integration registration and shared SDK helpers with hermetic tests; provisional output envelope is the main live-smoke follow-up, not a runtime regression risk.

Overview
Adds the Parallel Stripe Projects catalog family for parallel/api as a managed CatalogResource that exposes ${integrations.*.api_key} (provisional OUTPUT_FIELDS until mise run discover).

Registers ParallelApi in register_providers!, wires providers/parallel, and extends the catalog output drift test. stackless-provider-sdk gains optional/required boolean and optional integer config helpers for generated adapters.

Docs add PROVIDER-WAVES and a catalog-first decision; ADDING-A-PROVIDER points at waves. A generate_catalog_integrations.py script scaffolds remaining Phase 1 deployables (Parallel is the hand-landed slice of that rollout).

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Generator drops IMPLEMENTED providers

Medium Severity

generate_catalog_integrations.py rebuilds providers/mod.rs and register_providers! from only clerk, cloudflare, and families still being generated. parallel/api is landed in this PR but not added to IMPLEMENTED, so each generator run can rewrite providers/parallel/. Once parallel/api is marked implemented, the script omits pub mod parallel and the ParallelApi registry row, unregistering the provider.

Additional Locations (1)

• scripts/generate_catalog_integrations.py#L16-L32

 

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