fix: exclude quarterly windows from all PCA/SVD computation

- analysis/explorer_data.py: add AND window_id NOT LIKE '%-Q%' to
  _UNIFORM_DIM_SQL so quarterly windows are filtered at the source
- explorer.py: remove stale comment justifying quarterly inclusion;
  remove redundant '-Q' guard in SVD tab trajectory view
- scripts/recompute_svd.py: replace quarter_bounds() with year_bounds()
  that handles annual window IDs like '2024'; filter window list to
  annual-only before recomputing SVD

analysis/explorer_data.py

@@ -64,6 +64,7 @@ _UNIFORM_DIM_SQL = """
     SELECT window_id
     FROM dominant
     WHERE dim >= 25 AND cnt >= 10
+      AND window_id NOT LIKE '%-Q%'
     ORDER BY window_id
 """