Background STL analysis with computing spinner; manual geometry override

- analyse_in_background() runs in FastAPI BackgroundTasks with its own
  DB session; _in_progress set prevents duplicate concurrent analyses
- Job detail shows a spinner + auto-reloads every 3s while computing
- 'Compute now' button also triggers background analysis
- StlCache.manually_set flag (migration 0011): entries marked manual are
  never overwritten by auto-analysis
- 'Override values' collapsible form on job detail lets user set
  bounding box and volume directly from slicer data

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/routers/ui.py

@@ -4,7 +4,7 @@ import uuid as _uuid
 from datetime import datetime, timedelta
 from pathlib import Path
 
-from fastapi import APIRouter, Depends, File, Form, Request, UploadFile
+from fastapi import APIRouter, BackgroundTasks, Depends, File, Form, Request, UploadFile
 from fastapi.responses import FileResponse, HTMLResponse, RedirectResponse
 from fastapi.templating import Jinja2Templates
 from sqlalchemy import case, or_
@@ -26,7 +26,7 @@ from app.estimation import estimate  # also used in start_job
 from app.filamentdb import (available_colors, available_materials, find_matching_ams_roll,
                              get_stock, log_print_on_roll, spool_counts)
 from app.stl import get_stl_dir, list_stl_files
-from app.stl_analysis import analyse, get_cache_map  # noqa: F401 used in job_detail route
+from app.stl_analysis import analyse_in_background, get_cache_map, is_computing  # noqa: F401
 
 router = APIRouter()
 templates = Jinja2Templates(directory="app/templates")
@@ -260,13 +260,14 @@ async def create_job(
 
 
 @router.get("/jobs/{job_id}", response_class=HTMLResponse)
-def job_detail(job_id: int, request: Request, db: Session = Depends(get_db)):
+def job_detail(job_id: int, request: Request, background_tasks: BackgroundTasks, db: Session = Depends(get_db)):
     from fastapi import HTTPException
     job = db.query(PrintJob).filter(PrintJob.id == job_id).first()
     if not job:
         raise HTTPException(status_code=404, detail="Job not found")
 
     file_missing = False
+    computing = False
     stl = None
     if job.file_name:
         file_path = get_stl_dir() / job.file_name
@@ -275,7 +276,9 @@ def job_detail(job_id: int, request: Request, db: Session = Depends(get_db)):
         else:
             stl = db.query(StlCache).filter_by(filename=job.file_name).first()
             if stl is None and not job.file_name.endswith(".gcode"):
-                stl = analyse(job.file_name, db)
+                if not is_computing(job.file_name):
+                    background_tasks.add_task(analyse_in_background, job.file_name)
+                computing = True
 
     estimation = estimate(stl.volume_ccm, job.job_material) if stl and stl.volume_ccm else None
     return templates.TemplateResponse("job_detail.html", {
@@ -284,6 +287,7 @@ def job_detail(job_id: int, request: Request, db: Session = Depends(get_db)):
         "job": job,
         "stl": stl,
         "file_missing": file_missing,
+        "computing": computing,
         "estimation": estimation,
         "printers": db.query(Printer).order_by(Printer.name).all(),
         "brackets": db.query(JobBracket).order_by(JobBracket.name).all(),
@@ -457,14 +461,47 @@ def finish_job(job_id: int, db: Session = Depends(get_db)):
 
 
 @router.post("/jobs/{job_id}/analyse")
-def analyse_job_file(job_id: int, db: Session = Depends(get_db)):
+def analyse_job_file(job_id: int, background_tasks: BackgroundTasks, db: Session = Depends(get_db)):
     from fastapi import HTTPException
     job = db.query(PrintJob).filter(PrintJob.id == job_id).first()
     if not job or not job.file_name:
         raise HTTPException(status_code=404, detail="Job or file not found")
     db.query(StlCache).filter_by(filename=job.file_name).delete()
     db.commit()
-    analyse(job.file_name, db)
+    background_tasks.add_task(analyse_in_background, job.file_name)
+    return RedirectResponse(url=f"/jobs/{job_id}", status_code=HTTP_303_SEE_OTHER)
+
+
+@router.post("/jobs/{job_id}/geometry")
+def set_geometry(
+    job_id: int,
+    volume_ccm: float = Form(...),
+    cube_x: float = Form(...),
+    cube_y: float = Form(...),
+    cube_z: float = Form(...),
+    db: Session = Depends(get_db),
+):
+    from fastapi import HTTPException
+    job = db.query(PrintJob).filter(PrintJob.id == job_id).first()
+    if not job or not job.file_name:
+        raise HTTPException(status_code=404, detail="Job or file not found")
+    stl = db.query(StlCache).filter_by(filename=job.file_name).first()
+    if stl:
+        stl.volume_ccm = volume_ccm
+        stl.cube_x = cube_x
+        stl.cube_y = cube_y
+        stl.cube_z = cube_z
+        stl.manually_set = True
+    else:
+        db.add(StlCache(
+            filename=job.file_name,
+            volume_ccm=volume_ccm,
+            cube_x=cube_x,
+            cube_y=cube_y,
+            cube_z=cube_z,
+            manually_set=True,
+        ))
+    db.commit()
     return RedirectResponse(url=f"/jobs/{job_id}", status_code=HTTP_303_SEE_OTHER)