refactor: update migration files to maintain compatibility and remove redundant column additions

backend/src/db/migrations/0001_add_strips.sql

@@ -1 +1,3 @@
-ALTER TABLE medications ADD COLUMN strips integer NOT NULL DEFAULT 0;
+-- Migration 0001: strips column already exists in 0000_init.sql
+-- This file is kept for migration history compatibility
+SELECT 1;

backend/src/db/migrations/0002_pack_inventory.sql

@@ -1,15 +1,3 @@
-ALTER TABLE medications ADD COLUMN pack_count integer NOT NULL DEFAULT 1;
-ALTER TABLE medications ADD COLUMN strips_per_pack integer NOT NULL DEFAULT 1;
-ALTER TABLE medications ADD COLUMN tabs_per_strip integer NOT NULL DEFAULT 1;
-ALTER TABLE medications ADD COLUMN loose_tablets integer NOT NULL DEFAULT 0;
-
--- Backfill from previous fields where possible
-UPDATE medications
-SET
-  pack_count = COALESCE(pack_count, 1),
-  strips_per_pack = CASE WHEN strips IS NOT NULL THEN strips ELSE 1 END,
-  tabs_per_strip = CASE WHEN strip_size IS NOT NULL THEN strip_size ELSE 1 END,
-  loose_tablets = CASE
-    WHEN strip_size IS NOT NULL AND strips IS NOT NULL THEN MAX(count - (strips * strip_size), 0)
-    ELSE 0
-  END;
+-- Migration 0002: pack inventory columns already exist in 0000_init.sql
+-- This file is kept for migration history compatibility
+SELECT 1;