chore(android): replace math engine with RaTeX

[eszlamczyk]

What/Why?

Introduces new math engine - RaTeX - replacing Android math.

AndroidMath was unmaintained, required JitPack, and shipped libc++_shared.so which caused duplicate native library conflicts in instrumentation builds (Detox). It also used reflection-heavy metric extraction for baseline alignment of inline math.

What changed:

• build.gradle - swaps com.github.gregcockroft:AndroidMath for io.github.erweixin:ratex-android:0.1.9, removes the JitPack repository, and removes the packaging { pickFirsts } workarounds that existed solely for AndroidMath
• consumer-rules.pro - updates ProGuard keep rules from com.agog.mathdisplay.** / com.pvporbit.freetype.** to io.ratex.**
• MathInlineSpan - replaces MTMathView + reflection-based ascent/descent extraction with RaTeXEngine.parseBlocking + RaTeXRenderer drawn to a Bitmap; removes the reflection companion entirely
• MathMeasureHelper - drops the CountDownLatch/main-thread dispatch (no longer needed since RaTeX is allegedly thread-safe); renamed from measureOnMainThread to measure
• MathContainerView - replaces MTMathView with a lightweight inline View that renders synchronously via RaTeXEngine.parseBlocking

Testing

Start example app and try different markdown combinations via set markdown button (in playground - can be done one by one or via a combination):

$$E = mc^2$$

$$\psi(x, t) = A e^{i(kx - \omega t)}$$

$$\begin{aligned}
\nabla \cdot \mathbf{E} &= \frac{\rho}{\varepsilon_0} \\
\nabla \cdot \mathbf{B} &= 0 \\
\nabla \times \mathbf{E} &= -\frac{\partial \mathbf{B}}{\partial t} \\
\nabla \times \mathbf{B} &= \mu_0\mathbf{J} + \mu_0\varepsilon_0\frac{\partial \mathbf{E}}{\partial t}
\end{aligned}$$

$$\mathbf{R}_z(\theta) = \begin{bmatrix} 
\cos\theta & -\sin\theta & 0 \\ 
\sin\theta & \cos\theta & 0 \\ 
0 & 0 & 1 
\end{bmatrix}$$

$$f'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h}$$

$$\int_{-\infty}^{\infty} e^{-x^2} \, dx = \sqrt{\pi}$$

$$f(n) = \begin{cases} 
\frac{n}{2} & \text{if } n \text{ is even} \\ 
3n + 1 & \text{if } n \text{ is odd} 
\end{cases}$$

$$aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa$$

$a^2$

Random text with random $inline$ and $$a^2$$ 

Additionaly change apps/example/src/screens/playground/PlaygroundScreeen.tsx's MARKDOWN_STYLE fields (line 50) to include math and inlineMath stylings, for example:

math: {
  color: '#1e40aa',
  backgroundColor: '#eff6ff',
  padding: 12,
  marginTop: 8,
  marginBottom: 8,
  textAlign: 'center' as const,
},
inlineMath: {
  color: '#7c3aed',
},

PR Checklist

• Code compiles and runs on iOS
• Code compiles and runs on Android
• Updated documentation/README if applicable
• Ran example app to verify changes
• E2E tests are passing
• Required E2E tests have been added (if applicable)

[hryhoriiK97]

LGTM! This is a great change 🙌 I've left a few comments - please take a look at them 🙏

[eszlamczyk]

Note, bumping RaTeX in this pr as new version has important fix

[eszlamczyk]

Configuration	Size (MB)	Size (KB)
ratex + math=true	34MB	35,326.06 KB
ratex + math=false	31MB	31,807.24 KB
android math + math=true	33MB	34,014.68 KB
android math + math=false	31MB	31,807.24 KB