feat(filament): add spool count and total remaining weight columns

Adds computed spool statistics to filament list:
- spool_count: Number of non-archived spools of this filament
- total_remaining_weight: Sum of remaining weight across all spools

Backend changes:
- Modified database/filament.py find() to compute stats via subquery
- Added fields to Filament pydantic model in api/v1/models.py
- Updated filament API endpoint to include stats in response

Frontend changes:
- Added fields to IFilament interface
- Added columns to filament list table
- Added translation keys

Closes #15

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

spoolman/database/filament.py

@@ -114,13 +114,16 @@ async def find(
     sort_by: Optional[dict[str, SortOrder]] = None,
     limit: Optional[int] = None,
     offset: int = 0,
-) -> tuple[list[models.Filament], int]:
+) -> tuple[list[models.Filament], int, dict[int, tuple[int, float]]]:
     """Find a list of filament objects by search criteria.
 
     Sort by a field by passing a dict with the field name as key and the sort order as value.
     The field name can contain nested fields, e.g. vendor.name.
 
-    Returns a tuple containing the list of items and the total count of matching items.
+    Returns a tuple containing:
+    - list of filaments
+    - total count of matching items
+    - dict mapping filament_id to (spool_count, total_remaining_weight)
     """
     stmt = (
         select(models.Filament)
@@ -160,7 +163,25 @@ async def find(
     if total_count is None:
         total_count = len(result)
 
-    return result, total_count
+    # Fetch spool statistics for all filaments in the result
+    spool_stats: dict[int, tuple[int, float]] = {}
+    if result:
+        filament_ids = [f.id for f in result]
+        stats_stmt = (
+            select(
+                models.Spool.filament_id,
+                func.count(models.Spool.id).label("spool_count"),
+                func.coalesce(func.sum(models.Spool.initial_weight - models.Spool.used_weight), 0).label("total_remaining"),
+            )
+            .where(models.Spool.filament_id.in_(filament_ids))
+            .where((models.Spool.archived == False) | (models.Spool.archived == None))  # noqa: E712, E711
+            .group_by(models.Spool.filament_id)
+        )
+        stats_rows = await db.execute(stats_stmt)
+        for row in stats_rows.all():
+            spool_stats[row.filament_id] = (row.spool_count, float(row.total_remaining or 0))
+
+    return result, total_count, spool_stats
 
 
 async def update(