feat(abonnements): paliers LLM Essentielle/Premium, admin modeles par forfait, statistiques revenus, emails marketing

- Gamme officielle : Essentielle (Pro) = deepseek-v4-flash, glm-5.3-flash,
  minimax-m3 ; Premium (Business) = claude-sonnet-5, deepseek-v4-pro, glm-5.3
- Routage reel : le modele employe suit le palier IA du forfait (reglages
  admin > defaut du plan), garde anti-croisement de palier
- Nouvelle page admin « Modeles & abonnements » (matrice forfaits/paliers,
  modele par defaut, catalogue OpenRouter)
- Statistiques enrichies : revenus (30 j + total), MRR estime, credits,
  liste d'attente, paliers utilises
- Nouvelle page admin « Marketing » : audiences avec compteurs, apercu,
  envoi test obligatoire, historique, desabonnement public + en-tetes
  List-Unsubscribe ; .gitignore pour les donnees d'execution
- Interface (accueil + tarifs) alignee sur la gamme, 13 langues completes
- Tests : routage par palier (fonction + tache), marketing, revenus en base

tests/test_ai_tier_routing.py

@@ -0,0 +1,157 @@
+"""
+Routage réel des modèles par palier IA (spec « Stratégie LLM par abonnement »).
+
+- PLANS expose ai_models_essential / ai_models_premium (gamme officielle).
+- Un plan Pro (moteur openrouter) résout toujours un modèle Essentielle,
+  jamais un modèle Premium.
+- Le défaut admin (ai_tiers.<palier>.default_model) prime sur le défaut du
+  plan, sans redéploiement.
+"""
+
+import pytest
+from pathlib import Path
+from fastapi.testclient import TestClient
+
+from models.subscription import (
+    DEFAULT_AI_MODELS_ESSENTIAL,
+    DEFAULT_AI_MODELS_PREMIUM,
+    PLANS,
+    PlanType,
+)
+from routes.translate_routes import (
+    _allowed_providers_for_plan,
+    _plan_ai_models,
+    _resolve_tier_model,
+)
+
+
+@pytest.fixture
+def client(monkeypatch, tmp_path: Path):
+    """TestClient with JSON auth and rate limiting disabled."""
+    import services.auth_service as auth_svc
+    from middleware.rate_limiting import RateLimitManager
+
+    monkeypatch.setattr(auth_svc, "USERS_FILE", tmp_path / "users.json")
+    monkeypatch.setattr(auth_svc, "USE_DATABASE", False)
+    monkeypatch.setattr(auth_svc, "DATABASE_AVAILABLE", False)
+
+    async def _check_request_allow(self, request):
+        return True, "ok", "test"
+
+    async def _check_translation_allow(self, request, file_size_mb=0):
+        return True, "ok"
+
+    monkeypatch.setattr(RateLimitManager, "check_request", _check_request_allow)
+    monkeypatch.setattr(RateLimitManager, "check_translation", _check_translation_allow)
+
+    from main import app
+
+    return TestClient(app, raise_server_exceptions=True)
+
+
+def _settings(ai_tiers: dict | None = None):
+    from routes.admin_routes import SettingsConfig
+
+    if ai_tiers is None:
+        return SettingsConfig()
+    return SettingsConfig.model_validate({"ai_tiers": ai_tiers})
+
+
+# ---------------------------------------------------------------------------
+# Gamme officielle dans PLANS
+# ---------------------------------------------------------------------------
+def test_plans_expose_official_model_ranges():
+    essential = PLANS[PlanType.PRO]["ai_models_essential"]
+    assert essential == [
+        "deepseek/deepseek-v4-flash",
+        "z-ai/glm-5.3-flash",
+        "minimax/minimax-m3",
+    ]
+    business = PLANS[PlanType.BUSINESS]
+    assert business["ai_models_essential"] == essential
+    assert business["ai_models_premium"] == [
+        "anthropic/claude-sonnet-5",
+        "deepseek/deepseek-v4-pro",
+        "z-ai/glm-5.3",
+    ]
+
+
+def test_old_single_model_keys_removed():
+    assert "ai_model_essential" not in PLANS[PlanType.PRO]
+    assert "ai_model_essential" not in PLANS[PlanType.BUSINESS]
+    assert "ai_model_premium" not in PLANS[PlanType.BUSINESS]
+
+
+# ---------------------------------------------------------------------------
+# Résolution par palier
+# ---------------------------------------------------------------------------
+def test_pro_resolves_essential_plan_default():
+    assert _resolve_tier_model(_settings(), "pro", premium=False) == (
+        "deepseek/deepseek-v4-flash"
+    )
+
+
+def test_business_resolves_premium_plan_default():
+    assert _resolve_tier_model(_settings(), "business", premium=True) == (
+        "anthropic/claude-sonnet-5"
+    )
+
+
+def test_admin_tier_default_overrides_plan_default():
+    cfg = _settings(
+        {"essential": {"models": [], "default_model": "z-ai/glm-5.3-flash"}}
+    )
+    assert _resolve_tier_model(cfg, "pro", premium=False) == "z-ai/glm-5.3-flash"
+
+
+def test_admin_tier_models_first_used_when_default_empty():
+    cfg = _settings(
+        {
+            "essential": {
+                "models": ["minimax/minimax-m3", "deepseek/deepseek-v4-flash"],
+                "default_model": "",
+            }
+        }
+    )
+    assert _resolve_tier_model(cfg, "pro", premium=False) == "minimax/minimax-m3"
+
+
+def test_pro_never_resolves_premium_model():
+    cfg = _settings(
+        {
+            "essential": {"models": [], "default_model": ""},
+            "premium": {"models": [], "default_model": ""},
+        }
+    )
+    for plan_str in ("pro", "PlanType.PRO"):
+        model = _resolve_tier_model(cfg, plan_str, premium=False)
+        assert model in DEFAULT_AI_MODELS_ESSENTIAL
+        assert model not in DEFAULT_AI_MODELS_PREMIUM
+
+
+def test_pro_plan_does_not_allow_premium_provider():
+    allowed = _allowed_providers_for_plan(PlanType.PRO)
+    assert "openrouter" in allowed
+    assert "openrouter_premium" not in allowed
+
+
+def test_plan_fallback_for_plans_without_range():
+    # Free/Enterprise n'ont pas de liste : retombée sur la gamme officielle.
+    assert _plan_ai_models(PlanType.FREE, premium=False) == DEFAULT_AI_MODELS_ESSENTIAL
+    assert _plan_ai_models(PlanType.ENTERPRISE, premium=True) == DEFAULT_AI_MODELS_PREMIUM
+
+
+# ---------------------------------------------------------------------------
+# GET /plans expose les gammes (affichage public)
+# ---------------------------------------------------------------------------
+def test_get_plans_exposes_model_lists(client):
+    r = client.get("/api/v1/auth/plans")
+    assert r.status_code == 200
+    plans = {p["id"]: p for p in r.json()["data"]["plans"]}
+    assert plans["pro"]["ai_models_essential"] == [
+        "deepseek/deepseek-v4-flash",
+        "z-ai/glm-5.3-flash",
+        "minimax/minimax-m3",
+    ]
+    assert plans["business"]["ai_models_premium"][0] == "anthropic/claude-sonnet-5"
+    assert "ai_model_essential" not in plans["pro"]