Add Pydantic Logfire catalog integration

[snowmead]

Summary

• Phase 1 CatalogResource for pydantic/logfire (Wave 7).
• Registry row + providers/pydantic module, gap + hermetic provision tests.
• Provisional OUTPUT_FIELDS (api_key) until mise run discover pydantic/logfire.
• Branched from refresh tip 30df3de (plugin v0.25.0 fixtures). No smoke fixture.

Test plan

• cargo nextest run -p stackless-integrations -E 'test(pydantic)'
• registry uniqueness + catalog_outputs_match_output_fields
• mise run check (pre-push hook)

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Note

Low Risk
Follows the existing catalog-integration pattern with no auth or core infra changes; output field naming is explicitly provisional until discover is run.

Overview
Adds a Phase 1 Stripe Projects catalog integration for pydantic/logfire, so stacks can provision Logfire and wire integrations.*.api_key into service env.

New providers/pydantic module with PydanticLogfire: managed, global-only config (organization, project_name optional), resource kind integration-pydantic, and provisional api_key output until mise run discover pydantic/logfire. The integration is registered in registry.rs and included in the provider catalog_outputs_match_output_fields guard.

Tests cover catalog schema alignment against the shared fixture, plus hermetic provision asserting PYDANTIC_API_KEY maps to stored outputs.

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