Fix configuration toasts and default services to unlimited resources

[arjunkomath]

Summary

• remove duplicate success notifications from serverless, source, and environment-variable updates
• retain the shared configuration notification and all error feedback
• default newly created services to no CPU or memory limits
• stop generating resource limits in tc init manifests
• preserve existing service limits when a CLI manifest omits resources
• allow an explicit empty resources: {} block to remove limits
• retain all opt-in resource limit presets

Existing services keep their configured limits; this only changes defaults for newly created services.

Verification

• git diff --check
• go test ./internal/cli ./internal/manifest
• npx tsc --noEmit
• npx biome check actions/projects.ts lib/cli-service.ts components/service/details/resource-limits-section.tsx lib/constants.ts db/schema.ts
• Toast-only files were checked separately; Biome reports a pre-existing import-order issue in secrets-section.tsx

[github-actions]

React Doctor found no new issues. 🎉

_{Reviewed by React Doctor for commit ec58874.}