pdfdoc test: RE2 timing bound 1 s -> 10 s (race detector made it flaky: 1.0-1.9 s)

The check distinguishes linear time from catastrophic backtracking, which would never
finish on a 1 MB input, so a generous bound loses nothing. Reported by talos.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/plans/p5a/_files/internal/pdfdoc/pdfdoc_test.go

@@ -234,11 +234,14 @@ func TestGrepLimits(t *testing.T) {
 	if _, err := pdfdoc.Render(d, pdfdoc.Options{Grep: "(unclosed", OutCap: 1000}); !errors.Is(err, pdfdoc.ErrBadGrep) {
 		t.Errorf("bad regexp: %v, want ErrBadGrep", err)
 	}
-	// RE2 is linear: the classic catastrophic pattern over a 1 MB page finishes quickly.
+	// RE2 is linear: the classic catastrophic pattern over a 1 MB page finishes. A backtracking
+	// engine would not finish at all on this input, so the bound only has to be finite and far
+	// above normal: 10 s. (1 s was too tight under -race, which slows regexp ~15–20x: talos
+	// measured 1.5–1.9 s, 2026-09-26.)
 	evil := &pdftext.Doc{Meta: pdftext.Meta{Pages: 1}, Text: []string{strings.Repeat("a", 1<<20) + "!"}}
 	start := time.Now()
 	_, _ = pdfdoc.Render(evil, pdfdoc.Options{Grep: "(a+)+$", OutCap: 1000})
-	if d := time.Since(start); d > time.Second {
+	if d := time.Since(start); d > 10*time.Second {
 		t.Errorf("(a+)+$ took %v", d)
 	}
 	// Output stays under the cap.

internal/pdfdoc/pdfdoc_test.go

@@ -234,11 +234,14 @@ func TestGrepLimits(t *testing.T) {
 	if _, err := pdfdoc.Render(d, pdfdoc.Options{Grep: "(unclosed", OutCap: 1000}); !errors.Is(err, pdfdoc.ErrBadGrep) {
 		t.Errorf("bad regexp: %v, want ErrBadGrep", err)
 	}
-	// RE2 is linear: the classic catastrophic pattern over a 1 MB page finishes quickly.
+	// RE2 is linear: the classic catastrophic pattern over a 1 MB page finishes. A backtracking
+	// engine would not finish at all on this input, so the bound only has to be finite and far
+	// above normal: 10 s. (1 s was too tight under -race, which slows regexp ~15–20x: talos
+	// measured 1.5–1.9 s, 2026-09-26.)
 	evil := &pdftext.Doc{Meta: pdftext.Meta{Pages: 1}, Text: []string{strings.Repeat("a", 1<<20) + "!"}}
 	start := time.Now()
 	_, _ = pdfdoc.Render(evil, pdfdoc.Options{Grep: "(a+)+$", OutCap: 1000})
-	if d := time.Since(start); d > time.Second {
+	if d := time.Since(start); d > 10*time.Second {
 		t.Errorf("(a+)+$ took %v", d)
 	}
 	// Output stays under the cap.