Drop scheduled soak job; soak now runs inside precommit

The soak test only takes ~1s on an arm64 runner, so there's no point
keeping a nightly-only job for it. A companion change will flip
test/test_helper.exs to stop excluding :soak by default, so the next
precommit on main will exercise the memory harness on every PR.

Also drops the schedule: trigger entirely — nothing else wants it.

Author: ausimian

.github/workflows/ci.yml

@@ -5,9 +5,6 @@ on:
     branches: [main]
   pull_request:
     branches: [main]
-  schedule:
-    # Nightly soak at 03:17 UTC.
-    - cron: "17 3 * * *"
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -56,30 +53,3 @@ jobs:
       - run: mix deps.get
 
       - run: mix precommit
-
-  soak:
-    name: soak
-    # Soak is noisy (500 × 4 MB allocations); only run on the nightly
-    # schedule, not on every PR.
-    if: github.event_name == 'schedule'
-    runs-on: macos-14
-    env:
-      MIX_ENV: test
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Setup Beam
-        uses: erlef/setup-beam@v1
-        with:
-          version-file: .tool-versions
-          version-type: strict
-
-      - name: Cache MLX prebuilt
-        uses: actions/cache@v4
-        with:
-          path: ~/Library/Caches/emily
-          key: mlx-${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('mix.exs') }}
-
-      - run: mix deps.get
-      - run: mix compile
-      - run: mix test --only soak