feat(07.3-03): backend remember_me — TTL split + cookie Max-Age + 3 promoted tests

- services/auth.py: create_refresh_token gains remember_me=False param; selects 16h or 30d TTL (D-09, D-10, D-11)
- api/auth.py: LoginRequest.remember_me bool field; _set_refresh_cookie remember_me param for conditional max_age; login handler threads remember_me through both calls (D-11, RM-03)
- test_auth_es256.py: promote RM-01, RM-02, RM-03 stubs — all 9 phase tests now PASSED

backend/api/auth.py

@@ -59,6 +59,7 @@ class LoginRequest(BaseModel):
     password: str
     totp_code: Optional[str] = None
     backup_code: Optional[str] = None
+    remember_me: bool = False
 
 
 class ChangePasswordRequest(BaseModel):
@@ -68,8 +69,19 @@ class ChangePasswordRequest(BaseModel):
 
 # ── Helper: set httpOnly refresh cookie ──────────────────────────────────────
 
-def _set_refresh_cookie(response: Response, raw_token: str) -> None:
-    """Set the httpOnly Secure SameSite=Strict refresh cookie (CLAUDE.md constraint)."""
+def _set_refresh_cookie(
+    response: Response, raw_token: str, remember_me: bool = False
+) -> None:
+    """Set the httpOnly Secure SameSite=Strict refresh cookie (CLAUDE.md constraint).
+
+    remember_me=False (default): Max-Age = refresh_token_expire_hours * 3600 (16h, D-11, RM-03)
+    remember_me=True: Max-Age = refresh_token_expire_days * 86400 (30d, D-11, RM-03)
+    """
+    max_age = (
+        settings.refresh_token_expire_days * 86400
+        if remember_me
+        else settings.refresh_token_expire_hours * 3600
+    )
     response.set_cookie(
         key="refresh_token",
         value=raw_token,
@@ -77,7 +89,7 @@ def _set_refresh_cookie(response: Response, raw_token: str) -> None:
         secure=True,
         samesite="strict",
         path="/api/auth/refresh",
-        max_age=settings.refresh_token_expire_days * 86400,
+        max_age=max_age,
     )
 
 
@@ -276,8 +288,8 @@ async def login(
 
     # Issue tokens
     access_token = auth_service.create_access_token(str(user.id), user.role)
-    raw_refresh = await auth_service.create_refresh_token(session, user.id)
-    _set_refresh_cookie(response, raw_refresh)
+    raw_refresh = await auth_service.create_refresh_token(session, user.id, remember_me=body.remember_me)
+    _set_refresh_cookie(response, raw_refresh, remember_me=body.remember_me)
 
     # D-13: login success event
     await write_audit_log(

backend/services/auth.py

@@ -157,20 +157,30 @@ def decode_password_reset_token(token: str) -> str:
 
 # ── Refresh token lifecycle ─────────────────────────────────────────────────────
 
-async def create_refresh_token(session: AsyncSession, user_id: uuid.UUID) -> str:
+async def create_refresh_token(
+    session: AsyncSession, user_id: uuid.UUID, remember_me: bool = False
+) -> str:
     """Insert a new RefreshToken row and return the raw (unhashed) token string.
 
     The raw token is returned to the caller and set as an httpOnly cookie.
     Only the SHA-256 hash is stored in the database.
+
+    remember_me=False (default): TTL = refresh_token_expire_hours (16h short session, D-09, D-10)
+    remember_me=True: TTL = refresh_token_expire_days (30d extended session, D-11)
     """
     raw = secrets.token_urlsafe(32)
     token_hash = hashlib.sha256(raw.encode()).hexdigest()
     now = datetime.now(timezone.utc)
+    ttl = (
+        timedelta(days=settings.refresh_token_expire_days)
+        if remember_me
+        else timedelta(hours=settings.refresh_token_expire_hours)
+    )
     row = RefreshToken(
         id=uuid.uuid4(),
         user_id=user_id,
         token_hash=token_hash,
-        expires_at=now + timedelta(days=settings.refresh_token_expire_days),
+        expires_at=now + ttl,
         revoked=False,
     )
     session.add(row)

backend/tests/test_auth_es256.py

@@ -234,31 +234,94 @@ async def test_startup_rotation_idempotent(db_session):
     assert len(markers) == 1
 
 
+# ── RM helpers ───────────────────────────────────────────────────────────────
+
+
+async def _do_login(async_client, auth_user, remember_me: bool = False) -> dict:
+    """POST /api/auth/login for the auth_user and return the response."""
+    from tests.test_auth_api import FakeRedis
+    from main import app
+    app.state.redis = FakeRedis()
+    resp = await async_client.post(
+        "/api/auth/login",
+        json={
+            "email": auth_user["user"].email,
+            "password": "Testpassword123!",
+            "remember_me": remember_me,
+        },
+    )
+    return resp
+
+
 # ── RM-01: default TTL is 16 hours ───────────────────────────────────────────
 
 
-@pytest.mark.xfail(strict=True, reason="RM-01: not yet implemented")
 @pytest.mark.asyncio
 async def test_default_ttl_16_hours(async_client, db_session, auth_user):
-    pytest.xfail("not yet implemented")
+    from datetime import datetime, timezone, timedelta
+    from sqlalchemy import select
+    from db.models import RefreshToken
+
+    resp = await _do_login(async_client, auth_user, remember_me=False)
+    assert resp.status_code == 200
+
+    uid = auth_user["user"].id
+    result = await db_session.execute(
+        select(RefreshToken)
+        .where(RefreshToken.user_id == uid)
+        .order_by(RefreshToken.id.desc())
+    )
+    row = result.scalars().first()
+    assert row is not None
+
+    now = datetime.now(timezone.utc)
+    delta = row.expires_at.replace(tzinfo=timezone.utc) - now
+    assert timedelta(hours=15, minutes=30) < delta < timedelta(hours=16, minutes=30)
 
 
 # ── RM-02: remember_me TTL is 30 days ────────────────────────────────────────
 
 
-@pytest.mark.xfail(strict=True, reason="RM-02: not yet implemented")
 @pytest.mark.asyncio
 async def test_remember_me_ttl_30_days(async_client, db_session, auth_user):
-    pytest.xfail("not yet implemented")
+    from datetime import datetime, timezone, timedelta
+    from sqlalchemy import select
+    from db.models import RefreshToken
+
+    resp = await _do_login(async_client, auth_user, remember_me=True)
+    assert resp.status_code == 200
+
+    uid = auth_user["user"].id
+    result = await db_session.execute(
+        select(RefreshToken)
+        .where(RefreshToken.user_id == uid)
+        .order_by(RefreshToken.id.desc())
+    )
+    row = result.scalars().first()
+    assert row is not None
+
+    now = datetime.now(timezone.utc)
+    delta = row.expires_at.replace(tzinfo=timezone.utc) - now
+    assert timedelta(days=29, hours=23) < delta < timedelta(days=30, hours=1)
 
 
 # ── RM-03: cookie Max-Age values ─────────────────────────────────────────────
 
 
-@pytest.mark.xfail(strict=True, reason="RM-03: not yet implemented")
 @pytest.mark.asyncio
 async def test_remember_me_cookie_max_age(async_client, auth_user):
-    pytest.xfail("not yet implemented")
+    # Default (no remember_me): Max-Age = 16 * 3600 = 57600
+    resp_short = await _do_login(async_client, auth_user, remember_me=False)
+    assert resp_short.status_code == 200
+    # Parse raw Set-Cookie header for Max-Age
+    set_cookie_short = resp_short.headers.get("set-cookie", "")
+    assert "Max-Age=57600" in set_cookie_short
+
+    # With remember_me=True: Max-Age = 30 * 86400 = 2592000
+    resp_long = await _do_login(async_client, auth_user, remember_me=True)
+    assert resp_long.status_code == 200
+    set_cookie_long = resp_long.headers.get("set-cookie", "")
+    assert "Max-Age=2592000" in set_cookie_long
 
 
 # ── CFG-01 satellite: settings has jwt key fields ────────────────────────────