fix(codegen): sanitize progressive JSDoc metadata

[sarvesh1327]

Summary

• sanitize schema descriptions before rendering them into generated progressive tool JSDoc
• sanitize property descriptions plus category/keyword/short-description metadata in tool and index contexts
• add a regression test covering raw */ and newline injection from schema/category metadata

Test Plan

• cargo test -p mcp-execution-codegen progressive::generator --quiet
• cargo fmt --check
• cargo test -p mcp-execution-codegen --quiet
• cargo clippy -p mcp-execution-codegen --all-targets --all-features -- -D warnings