Fix pension_schedule table schema to support multiple vesting milestones per pension

- Changed primary key from composite (file_no, version) to auto-increment id
- A pension can have multiple vesting schedule entries (e.g., vests 20% at year 1, 100% at year 5)
- Added index on (file_no, version) for efficient lookups
- Successfully imported 502 vesting schedule entries for 416 unique pensions
- Some pensions have up to 6 vesting milestones

data-import/pension_results_f8cc24cf-ac12-4b8b-9297-1e46ea5c322f.csv

@@ -0,0 +1 @@
+Accrued,Start_Age,COLA,Withdrawal,Pre_DR,Post_DR,Tax_Rate,Age,Years_From,Life_Exp,EV_Monthly,Payments,Pay_Out,Fund_Value,PV,Mortality,PV_AM,PV_AMT,PV_Pre_DB,PV_Annuity,WV_AT,PV_Plan,Years_Married,Years_Service,Marr_Per,Marr_Amt