feat: per-position camera settings, material alias dialog, product delete, media browser links

- Per-render-position focal_length_mm/sensor_width_mm (DB → pipeline → Blender)
- FOV-based camera distance with min clamp fix for wide-angle lenses
- Unmapped materials blocking dialog on "Dispatch Renders" with batch alias creation
- Material check endpoint (GET /orders/{id}/check-materials)
- Batch alias endpoint (POST /materials/batch-aliases)
- Quick-map "No alias" badges on Materials page
- Full product hard-delete with storage cleanup (MinIO + disk files + orphaned CadFile)
- Delete button on ProductDetail page with confirmation
- Clickable product names in Media Browser (links to product page)
- Single-line render dispatch/retry (POST /orders/{id}/lines/{id}/dispatch-render)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/domains/materials/service.py

@@ -9,6 +9,7 @@ Resolution chain:
 3. Pass through unchanged → Blender will show FailedMaterial magenta
 """
 import logging
+from difflib import SequenceMatcher
 
 from sqlalchemy import create_engine, select, func
 from sqlalchemy.orm import Session, selectinload
@@ -138,3 +139,66 @@ async def seed_material_aliases_from_mappings(
         await db.flush()
 
     return {"created": created, "skipped": skipped}
+
+
+async def find_unmapped_materials(
+    material_names: list[str], db: AsyncSession
+) -> list[dict]:
+    """Find material names that have no alias or library match.
+
+    Returns a list of {"raw_name": str, "suggestions": [...]} for each
+    unmapped name. Suggestions are the top 5 SCHAEFFLER library materials
+    by string similarity.
+    """
+    if not material_names:
+        return []
+
+    # Load all aliases (case-insensitive lookup)
+    alias_rows = (await db.execute(select(MaterialAlias))).scalars().all()
+    alias_set: set[str] = {a.alias.lower() for a in alias_rows}
+
+    # Load all materials
+    mat_rows = (await db.execute(select(Material))).scalars().all()
+    # Library materials have a schaeffler_code
+    library_mats = [m for m in mat_rows if m.schaeffler_code is not None]
+    # All material names (case-insensitive) for exact-match check
+    name_lookup: dict[str, Material] = {m.name.lower(): m for m in mat_rows}
+
+    unmapped: list[dict] = []
+    seen: set[str] = set()
+
+    for raw_name in material_names:
+        raw_lower = raw_name.lower()
+        if raw_lower in seen:
+            continue
+        seen.add(raw_lower)
+
+        # 1. Alias match → mapped
+        if raw_lower in alias_set:
+            continue
+
+        # 2. Exact name match with a library material → mapped
+        matched_mat = name_lookup.get(raw_lower)
+        if matched_mat and matched_mat.schaeffler_code is not None:
+            continue
+
+        # Unmapped — compute suggestions from library materials
+        scored = []
+        for lib_mat in library_mats:
+            ratio = SequenceMatcher(None, raw_lower, lib_mat.name.lower()).ratio()
+            if ratio > 0.3:
+                scored.append((ratio, lib_mat))
+        scored.sort(key=lambda x: x[0], reverse=True)
+
+        suggestions = [
+            {
+                "id": str(m.id),
+                "name": m.name,
+                "schaeffler_code": str(m.schaeffler_code),
+            }
+            for _, m in scored[:5]
+        ]
+
+        unmapped.append({"raw_name": raw_name, "suggestions": suggestions})
+
+    return unmapped