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/alembic/versions/20261030_c4d7e9f021ab_news_risk.py

@@ -0,0 +1,78 @@
+"""Add independent news risk records; preserve existing data."""
+from alembic import op
+revision = 'c4d7e9f021ab'
+down_revision = 'b9d2e5f8a341'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.execute("""
+CREATE TABLE risk_settings (
+	id SERIAL NOT NULL,
+	enabled BOOLEAN NOT NULL,
+	provider_id INTEGER,
+	model VARCHAR(128) NOT NULL,
+	PRIMARY KEY (id),
+	FOREIGN KEY(provider_id) REFERENCES ai_providers (id)
+)
+    """)
+    op.execute("""
+CREATE TABLE risk_events (
+	id BIGSERIAL NOT NULL,
+	title TEXT NOT NULL,
+	category VARCHAR(64) NOT NULL,
+	entities JSONB NOT NULL,
+	stars INTEGER NOT NULL,
+	peak_stars INTEGER NOT NULL,
+	result JSONB NOT NULL,
+	published_at TIMESTAMP WITH TIME ZONE NOT NULL,
+	updated_at TIMESTAMP WITH TIME ZONE NOT NULL,
+	PRIMARY KEY (id)
+)
+    """)
+    op.execute('CREATE INDEX ix_risk_events_published_at ON risk_events (published_at)')
+    op.execute('CREATE INDEX ix_risk_events_updated_at ON risk_events (updated_at)')
+    op.execute("""
+CREATE TABLE risk_analyses (
+	id BIGSERIAL NOT NULL,
+	news_id BIGINT NOT NULL,
+	content_hash VARCHAR(64) NOT NULL,
+	state VARCHAR(16) NOT NULL,
+	event_id BIGINT,
+	input JSONB NOT NULL,
+	result JSONB,
+	model VARCHAR(128),
+	usage JSONB,
+	error TEXT,
+	started_at TIMESTAMP WITH TIME ZONE,
+	finished_at TIMESTAMP WITH TIME ZONE,
+	created_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL,
+	PRIMARY KEY (id),
+	UNIQUE (news_id, content_hash),
+	FOREIGN KEY(news_id) REFERENCES news_items (id),
+	FOREIGN KEY(event_id) REFERENCES risk_events (id)
+)
+    """)
+    op.execute('CREATE INDEX ix_risk_analyses_event_id ON risk_analyses (event_id)')
+    op.execute('CREATE INDEX ix_risk_analyses_news_id ON risk_analyses (news_id)')
+    op.execute('CREATE INDEX ix_risk_analyses_state ON risk_analyses (state)')
+    op.execute("""
+CREATE TABLE risk_snapshots (
+	id BIGSERIAL NOT NULL,
+	state VARCHAR(16) NOT NULL,
+	result JSONB,
+	quotes JSONB NOT NULL,
+	model VARCHAR(128) NOT NULL,
+	error TEXT,
+	created_at TIMESTAMP WITH TIME ZONE DEFAULT now() NOT NULL,
+	PRIMARY KEY (id)
+)
+    """)
+
+
+def downgrade():
+    op.drop_table('risk_snapshots')
+    op.drop_table('risk_analyses')
+    op.drop_table('risk_events')
+    op.drop_table('risk_settings')