ci: mutation testing is local only (D-59); the weekly run keeps proofs, oracle and fuzz

The owner, 2026-10-29: mutation testing is for local runs, not CI. The
weekly workflow's mutation shards (core, store, import, config, MCP) are
removed; they failed every week on the survivors and timeouts D-33
deferred to P12, and their red hid the run's real findings (a
fuzz_store_replay crash and a fuzz_settings_replay build break, both
being fixed). just mutants-* stays for the desktop; P12 runs the pass
whole. Recorded as D-59; the docs that said the shards keep running are
corrected.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp

.github/workflows/scheduled.yml

@@ -1,8 +1,7 @@
-# Weekly, and on demand: the slow layers (docs/testing.md).
-#
-# Mutation testing is split into shards (`just mutants-* k/n`), each its
-# own job, so every job ends well inside GitHub's six hours. The viewer has
-# no mutation job (owner, 2026-10-18).
+# Weekly, and on demand: the slow layers (docs/testing.md): the proofs,
+# the GnuCash oracle and the fuzz targets. Mutation testing is not run in
+# CI (owner, 2026-10-29, D-59): it is a local run (`just mutants-*`), and
+# P12 runs it whole on the owner's desktop.
 name: scheduled
 on:
   schedule:
@@ -39,79 +38,3 @@ jobs:
       - uses: actions/checkout@v4
       - uses: jdx/mise-action@v2
       - run: just fuzz ${{ matrix.target }} 600
-  mutants:
-    runs-on: ubuntu-24.04
-    timeout-minutes: 350
-    strategy:
-      fail-fast: false
-      matrix:
-        shard: [0, 1, 2, 3, 4, 5, 6, 7]
-    steps:
-      - uses: actions/checkout@v4
-      - uses: jdx/mise-action@v2
-      - run: just mutants ${{ matrix.shard }}/8
-      - if: always()
-        uses: actions/upload-artifact@v4
-        with:
-          name: mutants-core-${{ matrix.shard }}
-          path: mutants.out
-  mutants-store:
-    runs-on: ubuntu-24.04
-    timeout-minutes: 350
-    strategy:
-      fail-fast: false
-      matrix:
-        shard: [0, 1, 2, 3]
-    steps:
-      - uses: actions/checkout@v4
-      - uses: jdx/mise-action@v2
-      - run: just mutants-store ${{ matrix.shard }}/4
-      - if: always()
-        uses: actions/upload-artifact@v4
-        with:
-          name: mutants-store-${{ matrix.shard }}
-          path: mutants-store/mutants.out
-  mutants-import:
-    runs-on: ubuntu-24.04
-    timeout-minutes: 350
-    strategy:
-      fail-fast: false
-      matrix:
-        shard: [0, 1]
-    steps:
-      - uses: actions/checkout@v4
-      - uses: jdx/mise-action@v2
-      - run: just mutants-import ${{ matrix.shard }}/2
-      - if: always()
-        uses: actions/upload-artifact@v4
-        with:
-          name: mutants-import-${{ matrix.shard }}
-          path: mutants-import/mutants.out
-  mutants-config:
-    runs-on: ubuntu-24.04
-    timeout-minutes: 350
-    steps:
-      - uses: actions/checkout@v4
-      - uses: jdx/mise-action@v2
-      - run: just mutants-config
-      - if: always()
-        uses: actions/upload-artifact@v4
-        with:
-          name: mutants-config
-          path: mutants-config/mutants.out
-  mutants-mcp:
-    runs-on: ubuntu-24.04
-    timeout-minutes: 350
-    strategy:
-      fail-fast: false
-      matrix:
-        shard: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
-    steps:
-      - uses: actions/checkout@v4
-      - uses: jdx/mise-action@v2
-      - run: just mutants-mcp ${{ matrix.shard }}/16
-      - if: always()
-        uses: actions/upload-artifact@v4
-        with:
-          name: mutants-mcp-${{ matrix.shard }}
-          path: mutants-mcp/mutants.out