fix(tsrx): control flow expressions & text

[LuLaValva]

This example had two issues:

export default component Count() {
  let count = 0;

  <button onClick={() => {
    count++;
  }}>{count}</button>

  if (count > 5) {
    {"Large value"}
  }
}

1. The transformer didn't treat the if expression as an attribute, so even though it has > it wasn't being wrapped in parentheses
2. Text expressions do need to be prefixed with -- at the root level because of concise mode, but not in control flow tags

[coderabbitai]

Caution

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Walkthrough

The transform.ts file is refactored to standardize expression and statement rendering across control-flow helpers. The #emitIf, #emitForOf, and #emitSwitch functions now use #attrValue() instead of #slice() for condition/test expressions, while body emission switches to a new #blockStmts() helper. The #block helper is updated to emit block bodies via #blockStmts() and single statements via #child(). Additionally, a test fixture is added for a Count component that demonstrates state management, event handling, and conditional rendering.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'fix(tsrx): control flow expressions & text' directly refers to the main changes: fixes to control flow expression handling and text expression formatting in the tsrx transformer.
Description check	✅ Passed	The description clearly explains the two specific issues being fixed with code examples and technical context about concise mode and parentheses wrapping.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch control-flow-fixes

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