feat(task-023): bind workflow templates into demo flow

apps/backend/src/infrastructure/schema.py

@@ -148,6 +148,9 @@ POSTGRES_SCHEMA_STATEMENTS: tuple[str, ...] = (
     CREATE TABLE IF NOT EXISTS articles (
         id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
         target_site_id UUID NOT NULL REFERENCES target_sites(id),
+        workflow_template_id UUID REFERENCES workflow_templates(id),
+        workflow_template_version INTEGER,
+        workflow_template_snapshot JSONB,
         status TEXT NOT NULL CHECK (status IN ({ARTICLE_STATUS_VALUES})),
         publishing_status TEXT NOT NULL CHECK (
             publishing_status IN ({PUBLISHING_STATUS_VALUES})
@@ -162,6 +165,9 @@ POSTGRES_SCHEMA_STATEMENTS: tuple[str, ...] = (
         updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
     )
     """,
+    "ALTER TABLE articles ADD COLUMN IF NOT EXISTS workflow_template_id UUID REFERENCES workflow_templates(id)",
+    "ALTER TABLE articles ADD COLUMN IF NOT EXISTS workflow_template_version INTEGER",
+    "ALTER TABLE articles ADD COLUMN IF NOT EXISTS workflow_template_snapshot JSONB",
     """
     CREATE TABLE IF NOT EXISTS boundary_questions (
         id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
@@ -473,6 +479,10 @@ POSTGRES_SCHEMA_STATEMENTS: tuple[str, ...] = (
     ON articles (assigned_editor_id, updated_at DESC)
     """,
     """
+    CREATE INDEX IF NOT EXISTS idx_articles_workflow_template
+    ON articles (workflow_template_id, workflow_template_version)
+    """,
+    """
     CREATE INDEX IF NOT EXISTS idx_agent_jobs_queue
     ON agent_jobs (status, queued_at)
     """,
@@ -610,6 +620,9 @@ SQLITE_SCHEMA_STATEMENTS: tuple[str, ...] = (
     CREATE TABLE IF NOT EXISTS articles (
         id TEXT PRIMARY KEY,
         target_site_id TEXT NOT NULL,
+        workflow_template_id TEXT,
+        workflow_template_version INTEGER,
+        workflow_template_snapshot TEXT,
         status TEXT NOT NULL,
         publishing_status TEXT NOT NULL,
         brief_description TEXT NOT NULL,
@@ -900,6 +913,10 @@ SQLITE_SCHEMA_STATEMENTS: tuple[str, ...] = (
     ON articles (assigned_editor_id, updated_at)
     """,
     """
+    CREATE INDEX IF NOT EXISTS idx_articles_workflow_template
+    ON articles (workflow_template_id, workflow_template_version)
+    """,
+    """
     CREATE INDEX IF NOT EXISTS idx_agent_jobs_queue
     ON agent_jobs (status, queued_at)
     """,