feat: setup admin JSON generation and pdf viewer for free plan DPPs

backend/models.py

@@ -58,6 +58,7 @@ class User(SQLModel, table=True):
     tier: TierEnum = Field(default=TierEnum.FREE)
     trial_end: Optional[datetime] = None
     subscription_end: Optional[datetime] = None
+    profile_image_url: Optional[str] = None
     streak_count: int = Field(default=0)
     longest_streak: int = Field(default=0)
     created_at: datetime = Field(default_factory=datetime.utcnow)
@@ -186,3 +187,13 @@ class Subscription(SQLModel, table=True):
     status: str  # Active, Expired, Cancelled, Paused
     auto_renew: bool = Field(default=True)
     coupon_code: Optional[str] = None
+
+class SystemSettings(SQLModel, table=True):
+    id: str = Field(default="global", primary_key=True)
+    maintenance_mode: bool = Field(default=False)
+    allow_new_registrations: bool = Field(default=True)
+    enable_free_trial: bool = Field(default=True)
+    trial_duration_days: int = Field(default=5)
+    trial_tier: TierEnum = Field(default=TierEnum.AI_COACH)
+    updated_at: datetime = Field(default_factory=datetime.utcnow)
+