Use rounded database cards in the core themes

[konojunya]

Background

Database cylinder decoration competes with labels and creates an unnecessarily busy silhouette. The reviewed design uses a rounded card with the existing database icon.

Implementation Approach

• Use an 8 px rounded rectangle for database fallbacks across default, light, and dark.
• Preserve database colors, dimensions, typography, icons, and cache geometry.
• Prepare catalog and crate version 0.6.0 with generated artifact parity and release notes.

Testing Approach

• 24 Node tests, 3 Rust tests, publication guard tests, schema/security validation, generated parity, TypeScript, stable/MSRV Clippy and tests, rustdoc, Cargo publish dry run, and npm pack inspection.
• Reviewed full-diagram database card comparisons with unchanged routing and content.

Review Perspectives / Points of Concern

Catalog schema remains 1.0. No custom palette contract or new distribution channel is introduced. Consumers must explicitly upgrade the catalog; rendering and layout remain engine-owned.