Add AI news risk analysis and dashboard

Analyze news revisions with independent model settings, evidence-backed risk ratings, event grouping, and rolling market outlooks. Add a default homepage, archival history, pending-result refresh, and isolated regression coverage.

Keep analysis disabled until explicitly enabled. Require a separately authorized schema migration before deployment and preserve compatibility with the previous six-service instance.

backend/src/alphapulse/models/__init__.py

@@ -1,3 +1,4 @@
+from alphapulse.models.risk import RiskSettings, RiskEvent, RiskAnalysis, RiskSnapshot
 from alphapulse.core.db import Base
 from alphapulse.models.ai import AiProvider, ChatMessage, ChatSession, ContextVersion, SkillNode, SkillVersion
 from alphapulse.models.calendar import EconomicRelease, EconomicRevision, EconomicSeriesValue
@@ -6,6 +7,7 @@ from alphapulse.models.news import CrawlLog, CrawlRun, NewsItem, NewsRevision, R
 from alphapulse.models.trading import NewsSignal, TradingAccount, TradingAnalysis, TradingCredential, TradingEvent, TradingFill, TradingOrder, TradingSymbol
 
 __all__ = [
+    "RiskSettings", "RiskEvent", "RiskAnalysis", "RiskSnapshot",
     "AiProvider",
     "Base",
     "ChatMessage",

backend/src/alphapulse/models/risk.py

@@ -0,0 +1,56 @@
+"""Durable news risk analysis, events and dashboard snapshots."""
+from datetime import datetime
+from sqlalchemy import BigInteger, Boolean, DateTime, ForeignKey, Integer, String, Text, UniqueConstraint, func
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import Mapped, mapped_column
+from alphapulse.core.db import Base
+
+
+class RiskSettings(Base):
+    __tablename__ = 'risk_settings'
+    id: Mapped[int] = mapped_column(primary_key=True)
+    enabled: Mapped[bool] = mapped_column(Boolean, default=False)
+    provider_id: Mapped[int | None] = mapped_column(ForeignKey('ai_providers.id'))
+    model: Mapped[str] = mapped_column(String(128), default='')
+
+
+class RiskEvent(Base):
+    __tablename__ = 'risk_events'
+    id: Mapped[int] = mapped_column(BigInteger, primary_key=True)
+    title: Mapped[str] = mapped_column(Text)
+    category: Mapped[str] = mapped_column(String(64))
+    entities: Mapped[list] = mapped_column(JSONB)
+    stars: Mapped[int] = mapped_column(Integer)
+    peak_stars: Mapped[int] = mapped_column(Integer)
+    result: Mapped[dict] = mapped_column(JSONB)
+    published_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), index=True)
+    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), index=True)
+
+
+class RiskAnalysis(Base):
+    __tablename__ = 'risk_analyses'
+    __table_args__ = (UniqueConstraint('news_id', 'content_hash'),)
+    id: Mapped[int] = mapped_column(BigInteger, primary_key=True)
+    news_id: Mapped[int] = mapped_column(ForeignKey('news_items.id'), index=True)
+    content_hash: Mapped[str] = mapped_column(String(64))
+    state: Mapped[str] = mapped_column(String(16), default='pending', index=True)
+    event_id: Mapped[int | None] = mapped_column(ForeignKey('risk_events.id'), index=True)
+    input: Mapped[dict] = mapped_column(JSONB)
+    result: Mapped[dict | None] = mapped_column(JSONB)
+    model: Mapped[str | None] = mapped_column(String(128))
+    usage: Mapped[dict | None] = mapped_column(JSONB)
+    error: Mapped[str | None] = mapped_column(Text)
+    started_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+    finished_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
+
+
+class RiskSnapshot(Base):
+    __tablename__ = 'risk_snapshots'
+    id: Mapped[int] = mapped_column(BigInteger, primary_key=True)
+    state: Mapped[str] = mapped_column(String(16))
+    result: Mapped[dict | None] = mapped_column(JSONB)
+    quotes: Mapped[dict] = mapped_column(JSONB)
+    model: Mapped[str] = mapped_column(String(128))
+    error: Mapped[str | None] = mapped_column(Text)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())