🧹 [refactor] Break down excessively long build_dsl_registry function

[Tcode-Motion]

🎯 What: Extracted the schema insertion logic from the excessively long build_dsl_registry function into three domain-specific helper functions (register_web_schemas, register_canvas_schemas, and register_generic_schemas).
💡 Why: build_dsl_registry was nearly 500 lines long, making it hard to read and navigate. Breaking it down by logical module (Web, Canvas, Generic) greatly improves the maintainability and readability of dsl_schema.rs.
✅ Verification: Ran cargo test -p techscript_semantic and cargo test --workspace successfully, ensuring the same schemas are built and functionality is preserved without side effects.
✨ Result: A more modular and organized build_dsl_registry that is easier to maintain and extend in the future.

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PR created automatically by Jules for task 3064735118577765029 started by @Tcode-Motion

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