feat(integrations): add render-db Stripe catalog provider

[snowmead]

Summary

• Adds the render-db 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

Medium Risk
Introduces a paid database provisioning path with provisional credential output names until discover; behavior is covered by gap and hermetic tests but live envelope pinning is still pending.

Overview
Adds a Phase 1 Stripe Projects catalog integration for render/postgres (render-postgres), so stacks can provision managed Postgres and wire database_url into services.

The new render_db family implements the usual CatalogResource shape (config from catalog schema, managed/global-only hosting, registry row, catalog gap + hermetic provision tests). OUTPUT_FIELDS for DATABASE_URL are provisional until live mise run discover.

stackless-provider-sdk gains shared int_optional, bool_required, and bool_optional config readers for generated and hand-written catalog adapters.

Docs add PROVIDER-WAVES.md, a catalog-first decision in DECISIONS.md, and a cross-link from ADDING-A-PROVIDER.md. scripts/generate_catalog_integrations.py is introduced to scaffold remaining deployables (this PR lands render/postgres manually).

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Cursor Bugbot has reviewed your changes using default effort and found 2 potential issues.

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Script omits implemented render postgres

Medium Severity

This PR adds a hand-written render/postgres adapter, but IMPLEMENTED still lists only render/web-service and render/static-site. The generator therefore keeps treating render/postgres as missing and will rewrite postgres.rs, providers/mod.rs, and register_providers! on the next run, risking drift from the reviewed adapter.

 

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[cursor]

Generator drops skipped provider registrations

High Severity

generate_catalog_integrations.py rebuilds providers/mod.rs and the entire register_providers! block from only Clerk, Cloudflare, and services generated in that run. Catalog entries moved into IMPLEMENTED are skipped for generation but not preserved in the registry or module tree, so a later run can unregister adapters such as render-postgres while their source files remain.

 

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