feat: support transforming non-TS files (css, scss, svg, etc.)

[LouisLau-art]

Closes #189

This PR adds support for transforming path aliases in non-TS files such as .css, .scss, .svg, .png, etc.

Changes

• Updated resolveModuleName to check failedLookupLocations when TS fails to resolve a module.
• If the module name matches a path alias and the corresponding file exists (after removing TS-specific extensions like .ts, .tsx), it is now correctly transformed to a relative path.
• Added a test case in the general project to verify .css file transformation.

[kikiminyes]

Thanks for picking this up. I tested this branch locally:

• yarn compile passes
• yarn test currently fails in Transformer -> General Tests for test/projects/general/core/index.ts

The transform appears to emit the intended output for the new asset import (import "./styles.css";). The failing assertion looks like a test expectation issue: getExpected in test/tests/transformer/general.test.ts currently rewrites double-quoted alias specifiers, while the new fixture uses a single-quoted import (import '@core/styles.css';). Updating the fixture to double quotes or making getExpected handle both quote styles should make the regression test cover this case.