feat: Add spool adjustment history tracking (#6)

Track history of all spool weight/length adjustments with timestamps and comments:

Backend:
- Add SpoolAdjustment database model with spool_id, timestamp, type, value, comment
- Add Alembic migration for spool_adjustment table
- Add SpoolAdjustment Pydantic model for API responses
- Update use_weight, use_length, and measure functions to record adjustments
- Add GET /api/v1/spool/{id}/adjustments endpoint for history retrieval
- Add optional comment parameter to use/measure endpoints

Frontend:
- Add ISpoolAdjustment interface to spool model
- Add collapsible adjustment history table to spool show page
- Display timestamp, type (weight/length), amount, and comment
- Add translation keys for history table

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

client/public/locales/en/common.json

@@ -176,7 +176,15 @@
             "last_used": "Last Used",
             "registered": "Registered",
             "comment": "Comment",
-            "archived": "Archived"
+            "archived": "Archived",
+            "adjustment_history": "Adjustment History",
+            "show_history": "Show History",
+            "adjustment_timestamp": "Date/Time",
+            "adjustment_type": "Type",
+            "adjustment_type_weight": "Weight",
+            "adjustment_type_length": "Length",
+            "adjustment_value": "Amount",
+            "adjustment_comment": "Comment"
         },
         "fields_help": {
             "price": "Price of a full spool. If not set, the price of the filament will be assumed instead.",