ci: delegate Ubuntu testing to Aspect Workflows, simplify GitHub Actions

[acozzette]

Aspect Workflows already runs all Bazel versions across all workspaces on Linux, so the GHA Ubuntu matrix was redundant. GitHub Actions now only handles Mac/Windows smoke tests (gated to main), semantic PR validation, and a stable conclusion job for branch protection.

Also adds --config=ci globally in the Aspect Workflows config to activate CI-specific flags from tools/preset.bazelrc, and adds task IDs (bazel-7/8/9) to enable per-workspace overrides.

This aligns with the pattern we use for rules_js.

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Changes are visible to end-users: no

Test plan

• Covered by existing test cases
• New test cases added

[aspect-workflows]

Bazel 7 (Test)

5 test targets passed

Targets

//webpack/tests/devtool-override:write_bundle_test [k8-fastbuild]            70ms
//webpack/tests/simple:bundle_no_execroot_entry_point_matches [k8-fastbuild] 52ms
//webpack/tests/simple:entries_match [k8-fastbuild]                          45ms
//webpack/tests/simple:write_bundle_test [k8-fastbuild]                      55ms
//webpack/tests/worker:write_bundle_test [k8-fastbuild]                      22ms

Total test execution time was 244ms. 8 tests (61.5%) were fully cached saving 651ms.

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Bazel 8 (Test)

All tests were cache hits

10 tests (100.0%) were fully cached saving 1s.

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Bazel 9 (Test)

All tests were cache hits

10 tests (100.0%) were fully cached saving 1s.

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Bazel 7 (Test)

e2e/loaders

1 test target passed

Targets

//:test [k8-fastbuild]                                                       34ms

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Bazel 8 (Test)

e2e/loaders

All tests were cache hits

1 test (100.0%) was fully cached saving 36ms.

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Bazel 9 (Test)

e2e/loaders

All tests were cache hits

1 test (100.0%) was fully cached saving 31ms.

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Bazel 7 (Test)

e2e/loaders_jslib

1 test target passed

Targets

//:test [k8-fastbuild]                                                       27ms

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Bazel 8 (Test)

e2e/loaders_jslib

All tests were cache hits

1 test (100.0%) was fully cached saving 62ms.

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Bazel 9 (Test)

e2e/loaders_jslib

All tests were cache hits

1 test (100.0%) was fully cached saving 32ms.

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Bazel 7 (Test)

e2e/smoke

2 test targets passed

Targets

//src:bundles_0_test [k8-fastbuild]                                          22ms
//src:bundles_1_test [k8-fastbuild]                                          65ms

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Bazel 8 (Test)

e2e/smoke

All tests were cache hits

2 tests (100.0%) were fully cached saving 46ms.

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Bazel 9 (Test)

e2e/smoke

All tests were cache hits

2 tests (100.0%) were fully cached saving 120ms.

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Bazel 7 (Test)

e2e/worker

2 test targets passed

Targets

//:bundles_match [k8-fastbuild]                                              35ms
//:write_bundle_test [k8-fastbuild]                                          35ms

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Bazel 8 (Test)

e2e/worker

All tests were cache hits

2 tests (100.0%) were fully cached saving 64ms.

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Bazel 9 (Test)

e2e/worker

All tests were cache hits

2 tests (100.0%) were fully cached saving 67ms.

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Buildifier

[jbedard]

LGTM, but did you want to put macos in your branch name to verify this better?

[acozzette]

Sure, let me create a new branch just for testing but I'll leave this one around so that you don't have to approve another PR.