Wire shared browser types into starter TypeScript configs

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Summary

• Create starter TypeScript configuration from a packaged EEx template using Igniter.
• Include Volt-owned browser declarations instead of requiring application-local ImportMeta definitions.
• Update ordinary JSON configurations at the project root or in the standard asset directories while preserving options, explicit files, source discovery, and exclusions.
• Preserve JSONC and inherited/referenced configurations with actionable manual guidance.
• Provide shared declarations for CSS side-effect imports and CSS modules.

Validation

• mix ci: 711 passed, 5 skipped, 39 integration tests excluded.
• Fresh starter fixture checked with TypeScript 7.0.2, including CSS imports and HMR.
• Installer tests cover preservation, idempotency, nested paths, default discovery, and unsupported configurations.

No version bump or publication is included.