Add macOS arm64 sys-vm JIT and update CI runners

[huangminghuang]

Change Description

Adds the macOS arm64 sysio::vm::jit backend and the supporting runtime, test, benchmark, and CI changes needed to make it usable on Apple Silicon.

Concrete changes in this PR:

• Adds include/sysio/vm/aarch64.hpp, an AArch64 machine-code writer for WASM constants, params/locals, globals, memory load/store/size/grow, integer arithmetic and bit operations, integer division/remainder traps, structured control flow, br_table, direct internal calls, imported host calls, call_indirect, and softfloat-backed floating-point arithmetic/conversions.
• Wires the AArch64 writer into the normal sysio::vm::jit backend on macOS arm64 while keeping jit_profile limited to x86_64.
• Adds platform capability gates and public compile-time flags in config.hpp for x86_64, arm64, Apple, generic JIT availability, AArch64 JIT availability, and JIT profiling availability.
• Updates parser/writer interfaces so branch emitters know whether a target is a loop target, which lets the AArch64 backend generate the right stack-drop and timeout-poll behavior for structured branches.
• Preserves JIT metadata needed by AArch64 runtime dispatch, including tables, type aliases, and fast-function mappings used for checked call_indirect execution.
• Updates jit_execution_context for the AArch64 trampoline ABI, argument-array entry point, 16-byte stack-slot alignment, remaining_call_depth_offset() support for generated inline call-depth accounting, and call-depth restoration after execution.
• Updates executable-code allocation for Apple Silicon with MAP_JIT, pthread_jit_write_protect_np write windows, instruction-cache flushing after code emission/patching, and explicit generated-code enabled/disabled state tracking.
• Reworks timed execution and signal handling so AArch64 JIT uses thread-local timeout state, generated timeout polls, SIGILL handling, interrupted-PC inspection, and safe previous-handler chaining, while preserving existing page-revocation timeout behavior where supported.
• Adds AArch64 JIT regression coverage for constants, locals, large frames, memory offsets, direct/imported/indirect calls, control flow, br_table, globals, memory growth, softfloat operations, and trap behavior.
• Adds watchdog, allocator, signal, and backend regression tests for timeout delivery, cooperative timeout mode, concurrent shared-code interruption, late signals, repeated trap races, Apple JIT page permissions, and backend capability flags.
• Makes the generic watchdog interrupt test scheduler-tolerant by waiting for the watchdog callback instead of cancelling the guard after a fixed sleep, addressing the macOS 26 hosted-runner flake in run 27368839657 / job 80875404820.
• Adds an AArch64 interpreter-vs-JIT microbenchmark and benchmark report for the scalar sum_to workload.
• Updates the GitHub Actions workflow to run direct CMake/vcpkg builds on hosted Ubuntu 24.04 and macOS 26 runners with recursive checkout, ccache, bounded parallelism, and parallel CTest.
• Bumps the sys-vm package version from 1.1.1 to 1.2.0.

API Changes

• API Changes

No runtime WASM, host-function, or backend call API changes are intended. The PR does add public compile-time capability flags/macros so integrations can distinguish x86_64 JIT, Apple AArch64 JIT, and JIT profiling support.

Documentation Additions

• Documentation Additions

Includes the AArch64 JIT benchmark report. The downstream Wire development/full-suite testing process was also documented in the integration repository for local validation, but that documentation is not part of this eos-vm PR.

Testing

• PR head e95ba4b: rebuilt unit_tests in build/macos-arm64-port.
• PR head e95ba4b: watchdog CTest subset passed: 9/9 tests.
• PR head e95ba4b: exact failing watchdog interrupt test passed 50/50 repeats with ctest --repeat until-fail:50.
• PR head aee4e44: rebuilt unit_tests and aarch64_jit_benchmark in build/macos-arm64-port.
• PR head aee4e44: focused CTest slice for AArch64 JIT, watchdog, signal, allocator, null backend, and capability-flag coverage: 47/47 tests passed.
• Earlier full eos-vm CTest at 608e3dc, before the final unused-helper/test-flake cleanups: 5151/5151 tests passed.
• Wire downstream release configure/build at 608e3dc completed with:
  • CMAKE_BUILD_TYPE=Release
  • SYSIO_TEST_FORBIDDEN_PORTS=11434
  • VCPKG_TARGET_TRIPLET=arm64-osx
  • wire-sys-vm 1.2.0#10
• Wire standalone interrupt_trx_test at 608e3dc: 1/1 passed in 111.03 sec.
• Wire full long-running + nonparallelizable integration suite at 608e3dc: 105/105 passed with ctest -j9 in 1876.75 sec real time.