Integrate the expanded core icon catalog

[konojunya]

Background

Theme 0.4.0 expands the provider-neutral core icon catalog from 12 to 30 icons, and Engine 0.5.0 embeds that catalog. The native CLI still pinned Engine 0.4.0 and Theme 0.3.0, so offline CLI renders could not use the newly approved icons.

Implementation Approach

• Pin the merged Engine 0.5.0 and Theme 0.4.0 commits.
• Refresh the Rust lockfile without changing unrelated registry dependencies.
• Document all 30 bundled provider-neutral icon identifiers.
• Exercise the new gateway icon in the release render fixture and require its embedded SVG metadata.

Testing Approach

• cargo +stable fmt --check
• cargo +stable test --locked
• Canonical formatter conformance against the pinned specification revision
• Stable Clippy and rustdoc with warnings denied
• Rust 1.85 tests and Clippy
• Release build plus standalone SVG validation
• Coverage gates: 92.47% regions, 97.97% functions, 93.08% lines
• cargo audit --json: 0 vulnerabilities and 0 informational warnings

Review Perspectives / Points of Concern

• Confirm both Git dependencies point to the final merged provider commits.
• Confirm the CLI remains fully offline and bundles no vendor artwork.
• Confirm the render fixture proves a newly added core icon is available through the native binary.