fix: restore protocol baseline, resolve 403/400 registration errors, and fully remove deprecated playwright dependency

tests/test_email_service_backoff.py

@@ -0,0 +1,61 @@
+from src.services.base import (
+    EmailProviderBackoffState,
+    OTPTimeoutEmailServiceError,
+    RateLimitedEmailServiceError,
+    apply_adaptive_backoff,
+    calculate_adaptive_backoff_delay,
+)
+
+
+def test_calculate_adaptive_backoff_delay_uses_failure_count_progression():
+    assert calculate_adaptive_backoff_delay(0) == 30
+    assert calculate_adaptive_backoff_delay(1) == 30
+    assert calculate_adaptive_backoff_delay(2) == 60
+    assert calculate_adaptive_backoff_delay(3) == 120
+
+
+def test_apply_adaptive_backoff_tracks_timeout_failures_to_one_hour():
+    state = EmailProviderBackoffState()
+
+    first = apply_adaptive_backoff(
+        state,
+        OTPTimeoutEmailServiceError("等待验证码超时", error_code="OTP_TIMEOUT_SECONDARY"),
+        now=1000.0,
+    )
+    second = apply_adaptive_backoff(
+        first,
+        OTPTimeoutEmailServiceError("等待验证码超时", error_code="OTP_TIMEOUT_SECONDARY"),
+        now=1031.0,
+    )
+    third = apply_adaptive_backoff(
+        second,
+        OTPTimeoutEmailServiceError("等待验证码超时", error_code="OTP_TIMEOUT_SECONDARY"),
+        now=1092.0,
+    )
+
+    assert first.failures == 1
+    assert first.delay_seconds == 30
+    assert first.opened_until == 1030.0
+
+    assert second.failures == 2
+    assert second.delay_seconds == 60
+    assert second.opened_until == 1091.0
+
+    assert third.failures == 3
+    assert third.delay_seconds == 3600
+    assert third.opened_until == 4692.0
+
+
+def test_apply_adaptive_backoff_keeps_normal_rate_limit_on_exponential_curve():
+    state = EmailProviderBackoffState(failures=2, delay_seconds=60, opened_until=1060.0)
+
+    next_state = apply_adaptive_backoff(
+        state,
+        RateLimitedEmailServiceError("请求失败: 429", retry_after=7),
+        now=1100.0,
+    )
+
+    assert next_state.failures == 3
+    assert next_state.delay_seconds == 120
+    assert next_state.opened_until == 1220.0
+    assert next_state.retry_after == 7