fix: preserve resource configuration and verify write readback

[Tynwink2000]

Summary

• Preserve ordinary Bot and Pipeline configuration in resource reads while masking credentials, including credentials embedded in URLs.
• Verify submitted fields after Bot create/update and Pipeline apply, and verify copied configuration and distinct identity after Pipeline copy. Return verification_failed when observable fields do not match.
• Report verification scope, checked fields, and masked fields explicitly. Set verified only when the compared fields are fully verifiable and match.
• Preserve existing Bot credentials when updating configurations containing exact masked placeholders; reject placeholders that cannot be restored safely before sending an update.
• Document the configuration and verification behavior in all nine README languages.

Regression coverage

• Stateful write fixtures and successful responses that ignore submitted payloads.
• Missing fields, boolean changes, nested configuration mismatches, configuration clearing, and copied-resource identity/configuration mismatches.
• Credential masking, malformed credential-bearing URLs, and safe masked read/modify/write behavior.
• Stable machine-readable schema metadata and unchanged ordinary configuration values.

Validation

• go vet ./...
• go test -race ./...
• go build ./cmd/lbctl
• Management API regression: Bot and Pipeline create/read/update/delete, Pipeline copy, nested setting readback, and credential-preserving Bot read/modify/write. Temporary test resources were removed.