Update to Zig 0.17

Context

build.zig line 20 has a compat module specifically for Zig 0.16 std library replacements (Mutex, Condition, Instant). With Zig 0.17 released, those replacements should land in std proper and the compat shim can be retired.

Scope

• Bump minimum_zig_version in build.zig.zon to 0.17.0
• Audit src/utils/compat.zig and remove anything that 0.17's std now provides natively (Mutex / Condition / Instant)
• Update any 0.16-specific build API calls in build.zig (e.g. module/createModule signatures, addExecutable shape)
• Verify static, strip, link-libc build options still work
• Update CI workflow to install Zig 0.17
• Docs: bump the Zig version requirement in README

Verification

• zig build clean on macOS + Linux
• zig build -Dstatic=true still produces a static binary
• Existing test suite passes