fix(cli): rewrite import extensions in transpile output

[rathodkunj2005]

Closes #36399.

Summary

• Rewrite TypeScript extensions in static imports, re-exports, and string-literal dynamic imports during deno transpile (.ts/.tsx → .js, .mts → .mjs, .cts → .cjs).
• Preserve query/hash suffixes, declaration-file specifiers, non-TypeScript specifiers, and ordinary string literals.
• Add focused unit coverage for extension mapping and a spec regression covering static imports, re-exports, dynamic imports, and literal lookalikes.

Verification

• cargo check -p deno
• ./tools/format.js --check cli/tools/transpile.rs cli/tools/transpile/import_extensions.rs tests/specs/transpile/__test__.jsonc tests/specs/transpile/import_extensions.ts tests/specs/transpile/check_import_extensions.ts tests/specs/transpile/rewrite_import_extensions_emit.out
• rustc --edition=2024 --test cli/tools/transpile/import_extensions.rs -o /tmp/import_extensions_test && /tmp/import_extensions_test (2 passed)

AI assistance was used to investigate the issue and implement this change; I reviewed the resulting code and tests.