Add regression fixtures for the extraction heuristics

[idomy]

Why

The line between user-facing text and code (CSS classes, x === "system", routes) is heuristic. A growing set of small .tsx fixtures locks in correct behavior so future changes do not regress.

Task

• Add .tsx snippets under examples/fixtures/, each exercising one tricky case (a className ternary, a comparison operand, a template with a plural suffix, an aria-label, ...).
• Extend test/run.mjs to assert the expected extracted set for each.

Good first PR

Even one new fixture + assertion is valuable. If you find a case where extract gets it wrong, that is a bug — open it and (bonus) fix src/heuristics.mjs.

[AlvyRahman]

Hi, I would like to work on this issue.

[AlvyRahman]

Please assign me to this issue if you want me to work on it. Thanks. :)

[idomy]

done