feat: enhance UI, refactor services, improve templates and tests

- Replace image_extractor with pdf_image_extractor service
- Enhance pi_client with expanded API capabilities
- Improve summarizer service with additional features
- Update admin routes with more endpoints
- Add login page template
- Enhance detail page with comprehensive layout
- Improve search and trends pages
- Update base template with additional elements
- Refactor tests for better coverage
- Add validate_summary script
- Update project configuration and dependencies

app/database.py

@@ -62,8 +62,39 @@ def get_db():
         db.close()
 
 
+def _migrate(engine) -> None:
+    """自动给已有表补齐缺失的列（SQLite ALTER TABLE ADD COLUMN）。"""
+    import logging
+
+    logger = logging.getLogger(__name__)
+
+    # 定义需要确保存在的列：{表名: [(列名, 列类型 SQL), ...]}
+    _MIGRATIONS: dict[str, list[tuple[str, str]]] = {
+        "paper_summaries": [
+            ("figures_json", "TEXT"),
+        ],
+    }
+
+    with engine.connect() as conn:
+        for table, columns in _MIGRATIONS.items():
+            # 获取已有列名
+            existing = {
+                row[1]
+                for row in conn.execute(text(f"PRAGMA table_info({table})"))
+            }
+            for col_name, col_type in columns:
+                if col_name not in existing:
+                    conn.execute(
+                        text(
+                            f"ALTER TABLE {table} ADD COLUMN {col_name} {col_type}"
+                        )
+                    )
+                    logger.info("Migrated: %s.%s added", table, col_name)
+        conn.commit()
+
+
 def init_db(engine):
-    """创建所有 ORM 表 + FTS5 虚拟表。"""
+    """创建所有 ORM 表 + FTS5 虚拟表 + 自动迁移。"""
     from app.models import Base  # noqa: F811 — 避免循环导入，延迟导入
 
     Base.metadata.create_all(engine)
@@ -71,3 +102,4 @@ def init_db(engine):
         conn.execute(text(FTS5_CREATE_SQL))
         conn.execute(text(FTS5_TRIGGER_INDEX))
         conn.commit()
+    _migrate(engine)