refactor: make duckdb imports optional in analysis modules

Allow analysis modules to be imported in lightweight test environments
without duckdb installed. Modules that need duckdb for actual queries
still require it at runtime, but import-time failures are handled gracefully.

analysis/clustering.py

@@ -11,7 +11,13 @@ import logging
 from typing import Dict, List, Optional, Tuple
 
 import numpy as np
+
+try:
     import duckdb
+except (
+    Exception
+):  # pragma: no cover - import-time guard for environments without duckdb
+    duckdb = None  # type: ignore
 
 _logger = logging.getLogger(__name__)
 

analysis/explorer_data.py

@@ -9,7 +9,12 @@ from __future__ import annotations
 import logging
 from typing import Dict, List, Set, Tuple
 
+try:
     import duckdb
+except (
+    Exception
+):  # pragma: no cover - allow lightweight import without duckdb installed
+    duckdb = None  # type: ignore
 import numpy as np
 import pandas as pd
 

analysis/political_axis.py

@@ -18,7 +18,11 @@ from typing import Dict, List, Optional, Tuple
 
 import numpy as np
 from . import trajectory as _trajectory
+
+try:
     import duckdb
+except Exception:  # pragma: no cover - allow importing module in lightweight test envs
+    duckdb = None  # type: ignore
 
 _logger = logging.getLogger(__name__)
 

analysis/trajectory.py

@@ -15,7 +15,13 @@ from typing import Dict, List, Optional, Tuple
 
 import numpy as np
 import pandas as pd
+
+try:
     import duckdb
+except (
+    Exception
+):  # pragma: no cover - import-time guard for environments without duckdb
+    duckdb = None  # type: ignore
 
 try:
     from scipy.linalg import orthogonal_procrustes as _scipy_procrustes