runners: bump tts-reader memory limit 4Gi -> 8Gi

The github-runner-tts-reader pod was being OOMKilled (exit 137)
mid-`dotnet test` on the TtsReader 1000+ test suite. PR #21 CI
(the Windows -> Linux runner migration) flapped twice with the
"self-hosted runner lost communication" annotation before the
K8s-side symptoms surfaced via kubectl describe pod.

Requests bumped 1Gi -> 2Gi, limits 4Gi -> 8Gi. Comment added
inline so future fleet runs don't trip the same wall.

Unblocks PR #21 + the 9 other open TtsReader PRs that all rebase
through it.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/github-runner/github-runner.yaml

@@ -1726,13 +1726,17 @@ spec:
                   key: credential
             - name: RUN_AS_ROOT
               value: "false"
+          # Bumped 2026-05-25: previous 4Gi limit caused OOMKill (exit 137)
+          # mid-`dotnet test` on TtsReader's 1000+ test suite. PR #21 CI flapped
+          # twice with "runner lost communication" before the K8s side
+          # symptoms surfaced. 8Gi gives ~30% headroom over peak observed.
           resources:
             requests:
               cpu: "500m"
-              memory: "1Gi"
+              memory: "2Gi"
             limits:
               cpu: "2000m"
-              memory: "4Gi"
+              memory: "8Gi"
           volumeMounts:
             - name: runner-home
               mountPath: /home/runner