feat(backend): patient garden — deterministic growth from activities

GET /api/v1/me/{token}/garden computes the garden on the fly from taken doses,
check-ins/diary and finished questionnaires (no new table). Rules and texts in
config/garden.yaml: per-day caps, points only add up, answers never count.

Refs #118

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

tests/test_services_garden.py

@@ -0,0 +1,88 @@
+"""Garden (#118): deterministic growth from activities, daily caps, never shrinks, ignores answers."""
+
+from collections.abc import AsyncIterator
+from datetime import date, datetime, timedelta
+
+import pytest
+from httpx import ASGITransport, AsyncClient
+from sqlalchemy import select
+
+from app.config import Settings
+from app.core import clock
+from app.db import session
+from app.db.clinical import DailyCheckin, Dose
+from app.main import app
+from app.services.garden import compute, load_config
+from scripts.seed_demo import seed
+
+MEM = "sqlite+aiosqlite:///:memory:"
+NOW = datetime(2026, 10, 5, 14, 0)
+D = date(2026, 10, 5)
+
+
+def test_points_steps_and_daily_caps() -> None:
+    cfg = load_config()
+    one_diary = compute([("diary", D)], D)
+    assert one_diary.points == cfg.activities["diary"].points
+    # Five diary entries on one day count as one; on five days — five times.
+    assert compute([("diary", D)] * 5, D).points == one_diary.points
+    five_days = compute([("diary", D - timedelta(days=i)) for i in range(5)], D)
+    assert five_days.points == 5 * one_diary.points
+    assert five_days.steps == five_days.points // cfg.step_points
+    assert five_days.points_in_step == five_days.points % cfg.step_points
+
+
+def test_never_shrinks_and_future_ignored() -> None:
+    events = [("meds", D), ("diary", D), ("questionnaire", D)]
+    now = compute(events, D)
+    # A week without any activity takes nothing away.
+    assert compute(events, D + timedelta(days=7)).points == now.points
+    # Rows dated after the (demo) today are not counted yet.
+    assert compute([*events, ("diary", D + timedelta(days=1))], D).points == now.points
+
+
+def test_plants_grow_one_after_another() -> None:
+    cfg = load_config()
+    per_plant = cfg.stages_per_plant
+    g = compute([("questionnaire", D - timedelta(days=i)) for i in range(100)], D)
+    stages = [p.stage for p in g.plants]
+    assert stages == sorted(stages, reverse=True) and stages[0] == per_plant
+    assert sum(stages) == min(g.steps, per_plant * cfg.max_plants)
+    assert compute([], D).title == cfg.titles[0].title
+
+
+@pytest.fixture
+async def client(monkeypatch: pytest.MonkeyPatch) -> AsyncIterator[AsyncClient]:
+    monkeypatch.setattr(clock, "get_settings", lambda: Settings(_env_file=None, demo_clock=True))
+    clock.set_now(NOW)
+    await session.configure(identity_url=MEM, clinical_url=MEM)
+    async with AsyncClient(transport=ASGITransport(app=app), base_url="http://test") as c:
+        yield c
+    await session.configure()
+
+
+async def test_andrey_has_a_living_garden_that_grows_and_ignores_mood(client: AsyncClient) -> None:
+    token = (await seed(12)).andrey_token
+    url = f"/api/v1/me/{token}/garden"
+    before = (await client.get(url)).json()
+    assert before["steps"] >= 4 and before["plants"][0]["stage"] > 0
+
+    # Mood is an answer: a bad day and a good day grow the garden the same way.
+    async with session.get_clinical_session() as s:
+        rows = (await s.scalars(select(DailyCheckin).where(DailyCheckin.token == token))).all()
+        for r in rows:
+            r.mood = 1
+    assert (await client.get(url)).json()["points"] == before["points"]
+
+    # Taking a dose today adds points.
+    async with session.get_clinical_session() as s:
+        dose = Dose(token=token, prescription_id=1, planned_at=clock.now(), status="taken", answered_at=clock.now())
+        s.add(dose)
+    after = (await client.get(url)).json()
+    assert after["points"] >= before["points"]
+    assert any(i["activity"] == "diary" for i in after["today"])
+
+
+async def test_unknown_patient_404(client: AsyncClient) -> None:
+    await seed(0)
+    assert (await client.get("/api/v1/me/nobody/garden")).status_code == 404