Build Idriç for 32-bit ARMv7 Termux

[isomorphisms]

Summary

• cross-build the Idriç compiler and Chez runtime for the phone's 32-bit armeabi-v7a Termux ABI
• pin Android API 24, NDK 29.0.14206865, and the Chez commit that provides tarm7le
• publish a relocatable compiler bundle with structural ELF verification
• include an installer that runs an end-to-end compile-and-execute smoke test on the phone before activation

Boundary

The CI build proves the executables are ELF32 ARM EABI5 and use Android's 32-bit linker. It cannot execute the artifact on the x86-64 runner. Merge remains blocked until the bundle compiles and runs the included .idric fixture on the actual ARMv7 Termux device.