feat(integrations): add runloop Stripe catalog provider

[snowmead]

Summary

• Adds the runloop 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 SDK config helpers; no auth or lifecycle behavior changes. Provisional Runloop output envelope may need discover before live use.

Overview
Adds Runloop as a Phase 1 Stripe Projects catalog integration: runloop/sandbox is a managed CatalogResource with empty config, provisional api_key output (until mise run discover), plus catalog gap and hermetic provision tests. It is wired through register_providers!, pub mod runloop, and the shared assert_outputs_match test for RunloopSandbox.

SDK: stackless-provider-sdk gains int_optional, bool_required, and bool_optional config readers so generated catalog modules can map integer/boolean schema fields.

Docs & tooling: New PROVIDER-WAVES.md (parallel family PRs, merge gates, exclusions, wave table) and DECISIONS.md entry for catalog-first vs substrates later; ADDING-A-PROVIDER.md links to waves. scripts/generate_catalog_integrations.py scaffolds remaining deployables from catalog.json (registry/mod updates included).

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