fix: add compatibility for Zig 0.16 ArrayList and timer changes

- Replace legacy ArrayList initializers with `initCapacity()` in relevant
  places to support Zig 0.16, preserving compatibility with older
  releases.
- Update benchmarks to use platform time routines when std.time.Timer is
  removed in Zig 0.16, and switch to page_allocator where
  GeneralPurposeAllocator is no longer available.
- Expand workflow support to include Zig 0.16.0.
- Clarify version support and adaptation details in documentation.