Stop Windows CI failing on slow durable writes

.github/workflows/ci.yml

@@ -45,5 +45,10 @@ jobs:
       - run: cargo fmt --check
       - run: cargo clippy --all-targets --locked -- -D warnings
       # Timing-bounded tests (1 s and 5 s durable-write and retirement budgets) fail closed when the
-      # runner is contended: Windows runs them serially, Linux on two threads.
+      # runner is contended: Windows runs them serially, Linux on two threads. Temporary files stay
+      # on the workspace drive: a durable write's median was 6 to 9 ms on the Windows system drive
+      # and 0.2 to 0.6 ms there (3 runners, 30 October 2026).
       - run: cargo test --locked -- --test-threads=${{ matrix.os == 'windows-latest' && 1 || 2 }}
+        env:
+          TEMP: ${{ runner.temp }}
+          TMP: ${{ runner.temp }}

src/storage.rs

@@ -880,7 +880,11 @@ mod lock_race_tests {
     #[test]
     fn atomic_records_and_locks_work_beyond_max_path() {
         let home = tempfile::tempdir().unwrap();
-        let deep = home.path().join("PUBLIC-".repeat(30));
+        // Two components, so the path passes MAX_PATH however short the temporary root is.
+        let deep = home
+            .path()
+            .join("PUBLIC-".repeat(30))
+            .join("PUBLIC-".repeat(30));
         fs::create_dir_all(&deep).unwrap();
         let record = deep.join("PUBLIC-record.json");
         atomic_json(&record, &serde_json::json!({"PUBLIC":1})).unwrap();