fix: remove deprecated minimumSockTimeMinutes from API contract

[adityachoudhari26]

Parent: #969
Depends on: #971

What

Remove the deprecated minimumSockTimeMinutes field and make minimumSoakTimeMinutes the sole (required) field in the environment progression rule schema.

Changes

OpenAPI specs — remove old field, make new one required

• apps/api/openapi/schemas/policies.jsonnet
• apps/workspace-engine/oapi/spec/schemas/policy.jsonnet

Regenerate generated files

• apps/api/openapi/openapi.json
• apps/api/src/types/openapi.ts
• apps/web/app/api/openapi.ts
• apps/workspace-engine/oapi/openapi.json
• apps/workspace-engine/pkg/oapi/oapi.gen.go
• packages/workspace-engine-sdk/src/schema.ts
• e2e/api/schema.ts

API route handlers — remove dual-field logic

• apps/api/src/routes/v1/workspaces/policies.ts — Only use minimumSoakTimeMinutes
• packages/trpc/src/routes/policies.ts — Same cleanup

Docs — remove deprecation notice

• docs/policies/overview.mdx
• docs/policies/environment-progression.mdx

Notes

This should only be done after #971 (TF provider update) has been released and users have had time to upgrade.