feat: Phase 4 多租户隔离 + 四阶段升级测试 + CSS 统一化

Phase 4: org_id 注入 JWT/API 过滤/组织管理 CRUD/前端组织列
测试: tests/test_phase_upgrades.py 97项全覆盖
CSS: theme-modern.css 共享 mobile-card-list/status-dot/search-bar 等模式
修复: initial_data.py LLM配置 NOT NULL 约束, TopicResponse 含 org_id

platform/backend/app/database.py

@@ -38,14 +38,32 @@ Base = declarative_base()
 
 def init_db():
     Base.metadata.create_all(bind=engine)
-    # 迁移：为已有表添加 last_login 列
+    from sqlalchemy import text
     try:
-        from sqlalchemy import text
         with engine.connect() as conn:
+            # 迁移：为已有表添加列
             conn.execute(text("ALTER TABLE users ADD COLUMN IF NOT EXISTS last_login TIMESTAMP"))
+            conn.execute(text("ALTER TABLE llm_configs ADD COLUMN IF NOT EXISTS provider VARCHAR DEFAULT 'opencode-go'"))
+            conn.execute(text("ALTER TABLE llm_configs ADD COLUMN IF NOT EXISTS base_url VARCHAR"))
+            conn.execute(text("ALTER TABLE llm_configs ADD COLUMN IF NOT EXISTS api_key VARCHAR"))
+            try:
+                conn.execute(text("ALTER TABLE articles ADD COLUMN IF NOT EXISTS images JSON DEFAULT '{}'::json"))
+            except Exception:
+                conn.execute(text("ALTER TABLE articles ADD COLUMN IF NOT EXISTS images TEXT DEFAULT '{}'"))
+            for table, col, typ in [
+                ("users", "org_id", "VARCHAR DEFAULT 'default'"),
+                ("topics", "org_id", "VARCHAR DEFAULT 'default'"),
+            ]:
+                try:
+                    conn.execute(text(f"ALTER TABLE {table} ADD COLUMN IF NOT EXISTS {col} {typ}"))
+                except Exception:
+                    try:
+                        conn.execute(text(f"ALTER TABLE {table} ADD COLUMN {col} {typ}"))
+                    except Exception:
+                        pass
             conn.commit()
     except Exception:
-        pass  # SQLite 不支持 IF NOT EXISTS，但 create_all 对 SQLite 够用
+        pass  # SQLite 不支持 IF NOT EXISTS，但 create_all 对 SQLite 够用，这里仅为 PostgreSQL 迁移
 
 def get_db():
     db = SessionLocal()