Fix broken cross-platform CI builds

[espmaniac]

Summary

• pin vshymanskyy/uvwasi to commit 0820128569533c855d60c0f6382acbb14aa62ad2
• pass the correctly typed function name to v_FindFunction() in C++ builds
• expand SnapshotGetModule() into an unambiguous loop for strict RISC-V GCC
• make runtime snapshots optional through d_m3HasSnapshot=0 or BUILD_SNAPSHOT=OFF
• make fuel/resume optional through d_m3HasFuel=0, while keeping it enabled by default everywhere except the flash-constrained ATmega1284P example
• use AVR call-prologue sharing and linker relaxation for the ATmega1284P build
• keep the shared, flash-saving fuel dispatcher unchanged when fuel is enabled
• give nested wasm3 self-hosting tests enough VM stack to report guest stack overflow correctly
• skip Particle cloud builds cleanly when PARTICLE_TOKEN is unavailable
• validate CoreMark with deterministic component CRCs, independent of runner speed and iteration count

Root causes

The original 50-job matrix had 15 failures:

• eleven uvwasi-dependent jobs requested the removed master branch and stopped during configuration
• two maintenance C++ jobs rejected a void * argument passed to a const char * parameter
• Sipeed MAIX promoted ambiguous loop indentation to an error
• ATmega1284P exceeded flash by 3860 bytes

Follow-up runs exposed additional latent problems:

• PlatformIO application flags did not reliably reach wasm3 library sources, so feature defaults belong in m3_config.h
• snapshot code was not the AVR overflow source: LTO was already discarding its unused API; fuel/resume and repeated AVR prologues needed their own size controls
• nested wasm3 has two VM stack layers; the previous 2 MiB outer stack was exhausted before the inner VM could return the expected stack overflow trap
• the push-only Particle job attempted to authenticate with an empty secret
• CoreMark's final CRC changes with its iteration count even though the deterministic list, matrix, and state CRCs remain correct

Validation

• configured and built with BUILD_WASI=uvwasi against the pinned dependency
• configured and built with strict misleading-indentation diagnostics
• configured, built, and tested with BUILD_SNAPSHOT=OFF
• passed the generated fuel regression test with fuel enabled
• passed 17,863/17,863 WebAssembly spec assertions with fuel both enabled and compiled out
• passed all seven fast WASI applications with fuel compiled out
• passed the complete nested/self-hosted WebAssembly spec suite: 17,863/17,863
• passed all seven fast WASI applications through nested wasm3, including both smallpt variants
• passed all 12 full local WASI application tests, including CoreMark
• verified ATmega1284P defaults are explicitly overrideable and other targets retain fuel and snapshots
• parsed the updated GitHub Actions workflow successfully
• measured a 2856-byte native text reduction with fuel compiled out and 2936 bytes with snapshots compiled out
• GitHub Actions run c_operations needs to be cleaned up wasm3/wasm3#63 completed successfully, including ATmega1284P, ESP8266, RISC-V, self-hosted WASI, C++, and macOS/uvwasi