feat(web_core): expand conformance suite coverage and unskip tests

[gspencergoog]

Summary

Implements graph topology validation and strict schema mode in TypeScript web core to achieve 100% conformance test suite pass rate with zero skipped tests.

Changes

• MessageProcessor:
  • Implemented validateTopology graph integrity checks (missing root component, circular reference detected, dangling reference, orphaned component).
  • Added strict theme and catalog component Zod schema validation when strictMode: true option is passed.
• SurfaceComponentsModel:
  • Added size, keys, and values accessors to support component collection inspection during topology graph traversal.
• Conformance Harness (conformance_test.mjs):
  • Added jsonSchemaToZod converter for dynamic YAML test catalog component and theme definitions.
  • Passed strictMode: Boolean(testCase.strictMode) to MessageProcessor.
  • Cleared SKIP_TEST_NAMES so all 221 conformance test vectors execute and pass.

Impact & Risks

• Impact: All Web Core conformance test vectors (221/221) now run and pass successfully.
• Risks: None. Topology and strict schema validation are gated by strictMode.

Testing

1. Run unit tests:

   yarn --cwd typescript/web_core test

   Verify 291/291 unit tests pass.

2. Run conformance harness:

   node typescript/web_core/tests/conformance/conformance_test.mjs

   Verify 221/221 test cases pass with 0 failed and 0 skipped.

[gemini-code-assist]

Code Review

This pull request implements support for normalizing v0.8 components, handles structured contents in data model updates, and falls back to the first catalog if catalogId is omitted. It also updates several conformance tests to validate these changes. The review feedback suggests several improvements for robustness: ensuring normalizeV08Component returns a safe fallback object and uses unknown instead of any; avoiding the spread operator to prevent property collisions; using the in operator instead of nullish coalescing to preserve explicit null values in data model updates; and replacing truthiness checks with nullish coalescing or explicit undefined checks to prevent valid falsy values (like 0 or empty strings) from being incorrectly overridden.