`mlugg/setup-zig` was chasing mirrors for ~4 minutes on every run
(see v0.0.1 / v0.0.2 logs) and `actions/setup-go` was spending
another ~4 minutes downloading Go before patterm started building.
mise already manages the project's zig pin; adding `go = "1.26.3"`
to `.mise.toml` (matching go.mod) lets `jdx/mise-action@v2` install
both with one cached step. Subsequent runs reuse the mise cache
instead of re-resolving mirror URLs and re-downloading toolchains.
Also adds an `actions/cache@v4` step for `~/.cache/go-build` and
`~/go/pkg/mod` keyed on `go.sum` so `go build` itself doesn't
re-pull modules every tag push.
Added .mise.toml pinning zig = "0.15.2" (the minimum the vendored
Ghostty commit requires) and taught the Makefile to resolve zig
through mise when available, falling back to PATH. Contributors run
`mise install` once and `make deps` just works.
Re-ran the pipeline benchmarks after rebuilding libghostty-vt with
ReleaseFast (same hardware, AMD Ryzen 7 7800X3D):
Debug ReleaseFast speedup
Pipeline 8-colour @120fps 63 fps 2030 fps 32x
Pipeline truecolor @120fps 34 fps 931 fps 27x
Emulator-only truecolor 34 fps 2051 fps 60x
7-16x headroom over 120 fps for the heaviest workload (truecolor
full-screen redraws). Static library size 33 MiB -> 13 MiB.
TODO.md baseline numbers updated to reflect post-fix throughput;
the "Debug-mode lib" finding is folded into the result it produced
rather than left as an open item.
harry