update to latest buildkit

[gilescope]

Makes ubuntu-latest CI reliably green by fixing the actual flake sources, and points buildkitd at a diagnostics-enabled BuildKit fork revision so the next unknown failure names its root cause instead of context canceled.

Companion fork PR: EarthBuild/buildkit#14

Merge these PRs first to reduce diff size

Each is an independent, self-contained extraction that lands on current main without the bump:

• fix: data race squashed #567 — data race in util/stringutil Caser (+ -race regression test)
• feat: better error diagnostics #568 — exit-code-126 diagnostic in the debugger wrapper
• feat: push tests down - test more at go level #569 — push tests down: AST VERSION parsing → Go tests; drop superseded integration tests
• test: cover doc command output in Go #570 — doc command output coverage in Go; trim doc integration tests to smoke
• test: add Go CLI test harness; remove superseded integration targets #571 — Go CLI test harness; remove superseded integration targets
• feat: process-memory + buildkitd OTEL telemetry for CI memory diagnos… #572 — CI memory telemetry (process-memory + buildkitd OTEL)
• feat: surface BuildKit root-cause on cancellation #574 — surface BuildKit root-cause on cancellation (failure diagnostics) — land after feat: process-memory + buildkitd OTEL telemetry for CI memory diagnos… #572 (uses statsstreamparser.Reset)
• docs: update buildkit/fsutil fork URLs to EarthBuild org #575 — update buildkit/fsutil fork URLs to EarthBuild org (docs)
• ci: fix bash array quoting + shellcheck annotations #576 — bash array-quoting + shellcheck annotation CI fixes
• ci: retry/back off toolchain downloads #577 — retry/backoff on toolchain downloads (zig, kind, antlr, gcloud, golangci-lint)

Once the above land, this PR is reduced to the genuine bump: go.mod/go.sum (buildkit/containerd v2/grpc 1.80), buildkitd, the BuildKit-API adaptations (entitlements, protobuf getters, ALPN), and the OOM/retry CI tuning.

Flake classes fixed

1. Network-fetch flake (dominant). +base fetched the Go toolchain with a bare wget; dl.google.com drops connections mid-transfer, +base dies, and every dependent target reports context canceled — which made BuildKit look guilty. Downloads now resume (wget -c) and retry with backoff; GNU curl sites get --retry --retry-all-errors. Same treatment for zig (ziglang.org throttles CI), gh, kind, antlr, golangci-lint. (Split out as ci: retry/back off toolchain downloads #577.)
2. Data race. Package-level shared cases.Caser in util/stringutil (x/text Casers are stateful, not goroutine-safe) panicked -race jobs with slice bounds out of range. Now constructed per call; concurrent regression test added. (Split out as fix: data race squashed #567.)
3. Nested-build cancellation. BuildKit fork revision 85c7359 preserves first non-cancellation root causes across cancellation fan-out (exec/cache/gateway/session paths), so genuine BuildKit failures surface with target/command context. Workflow retry harness restarts buildkitd between attempts. (earth-side diagnostics split out as feat: surface BuildKit root-cause on cancellation #574.)

Also in this branch

• CI memory telemetry, swap headroom, serialized slow nested test groups, staged buildkitd reuse.
• Exit-code-126 explanations and edge-merge subbuild fixes in the fork.

Verification

• go test -race ./util/stringutil/ red before the caser fix, green after (×3 runs).
• Retry-loop control flow tested for first-try success / eventual success / total failure; busybox wget flag support verified against alpine:3.18.

[github-actions]

⚠️ Are we earthbuild yet?

Warning: "earthly" occurrences have increased by 186 (3.48%)

📈 Overall Progress

Branch	Total Count
main	5346
This PR	5532
Difference	+186 (3.48%)

📁 Changes by file type:

File Type	Change
Go files (.go)	❌ +6
Documentation (.md)	❌ +14
Earthfiles	➖ No change

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Keep up the great work migrating from Earthly to Earthbuild! 🚀

💡 Tips for finding more occurrences

Run locally to see detailed breakdown:

./.github/scripts/count-earthly.sh

Note that the goal is not to reach 0.
There is anticipated to be at least some occurences of earthly in the source code due to backwards compatibility with config files and language constructs.

[gemini-code-assist]

Code Review

This pull request updates repository references and URLs from the 'earthly' organization to 'EarthBuild' across documentation and build configurations. It also performs a significant update of Go dependencies, including upgrading gRPC to v1.80.0 and updating various containerd and Docker-related packages. A bug was identified in the buildkitd/Earthfile where a log message references an undefined variable ${BUILDKIT_BRANCH} instead of ${BUILDKIT_GIT_BRANCH}.

[gemini-code-assist]

The variable ${BUILDKIT_BRANCH} is used in this log message, but the argument defined in this scope is BUILDKIT_GIT_BRANCH. This will result in an empty string being printed for the branch name in the logs. Since you are already modifying this line to parameterize the organization, you should also correct the branch variable name.

            echo "pinning github.com/${BUILDKIT_GIT_ORG}/buildkit@${BUILDKIT_GIT_BRANCH} to reference git sha1: $buildkit_sha1"; \

[gilescope]

21 green CI jobs! It's a start.