printers: printer installer map + install-batch endpoint

Rebuilds the classic printer-installer feature: pick printers on the shopfloor
map, download a .bat that installs them.

Backend (asset_routes.py): GET /api/printers/install-batch?printerids=1,2,3
returns a .bat attachment. Groups printers the way the classic installprinter.asp
did - HP/Xerox via the universal PrinterInstaller.exe /PRINTER="a,b,c", printers
with a .exe installpath via that installer /SILENT, and anything else (no
installpath, or a .zip) listed for manual install instead of being run blindly.
Download URLs derive from the site_base_url setting + the IIS-served /installers
folder (no hardcoded host). Reuses the existing install-list query shape.

Frontend: PrinterInstallerMap.vue - full-screen Leaflet shopfloor map (reuses
mapConfig), a marker per network printer at its mapx/mapy, click to toggle-select,
sidebar with the selection + an Install button that downloads the batch. Toplevel
route /printer-installer, printersApi.installList(), and an Installer Map button
on the printers list.

Tests: install-batch grouping (universal/specific/manual) + requires-ids.

tests/test_plugins/test_printer_install_batch.py

@@ -0,0 +1,77 @@
+"""Tests for the printer installer batch endpoint (/api/printers/install-batch).
+
+The printer installer map lets a user pick printers on the shopfloor map and
+download a .bat that installs them, grouping the same way the classic
+installprinter.asp did (HP/Xerox -> universal PrinterInstaller.exe; other
+printers with a .exe installpath -> that installer /SILENT; anything else ->
+manual).
+"""
+
+import pytest
+
+
+@pytest.fixture
+def printer_assettype(db):
+    from shopdb.core.models import AssetType
+    at = AssetType(assettype='printer', pluginname='printers',
+                   tablename='printers', description='Printers')
+    db.session.add(at)
+    db.session.commit()
+    return at
+
+
+def _vendor(db, name):
+    from shopdb.core.models import Vendor
+    v = Vendor(vendor=name)
+    db.session.add(v)
+    db.session.commit()
+    return v
+
+
+def _make_printer(client, auth_headers, **payload):
+    resp = client.post('/api/printers', json=payload, headers=auth_headers)
+    assert resp.status_code == 201, resp.get_json()
+    return resp.get_json()['data']['printer']['printerid']
+
+
+def test_install_batch_groups_universal_specific_and_manual(
+        client, db, auth_headers, printer_assettype):
+    hp = _vendor(db, 'HP')
+    zebra = _vendor(db, 'Zebra')
+    epson = _vendor(db, 'Epson')
+
+    # HP -> universal installer
+    hp_id = _make_printer(client, auth_headers, assetnumber='CSF04-WJRP2035-HP',
+                          hostname='wjprn04', vendorid=hp.vendorid)
+    # Zebra with a .exe installpath -> specific silent install
+    zebra_id = _make_printer(client, auth_headers, assetnumber='LABELER-ZEBRA',
+                             hostname='wjprn05', vendorid=zebra.vendorid,
+                             installpath='./installers/printers/zddriver.exe')
+    # Epson with a .zip installpath -> manual (we do not run a .zip /SILENT)
+    epson_id = _make_printer(client, auth_headers, assetnumber='RECEIPT-EPSON',
+                             hostname='wjprn06', vendorid=epson.vendorid,
+                             installpath='./installers/printers/c350navi.zip')
+
+    ids = '%d,%d,%d' % (hp_id, zebra_id, epson_id)
+    resp = client.get('/api/printers/install-batch?printerids=' + ids,
+                      headers=auth_headers)
+    assert resp.status_code == 200
+    assert 'application/octet-stream' in resp.headers['Content-Type']
+    assert '.bat' in resp.headers['Content-Disposition']
+
+    bat = resp.get_data(as_text=True)
+    # Universal group: HP printer name in a /PRINTER list + PrinterInstaller.exe
+    assert 'PrinterInstaller.exe' in bat
+    assert '/PRINTER="CSF04-WJRP2035-HP"' in bat
+    # Specific: the .exe installpath resolved + run /SILENT
+    assert 'installers/printers/zddriver.exe' in bat
+    assert '/SILENT' in bat
+    # Manual: the .zip printer is flagged, NOT executed
+    assert 'MANUAL' in bat
+    assert 'RECEIPT-EPSON' in bat
+    assert 'c350navi.zip' not in bat  # never handed to the runner
+
+
+def test_install_batch_requires_ids(client, db, auth_headers, printer_assettype):
+    resp = client.get('/api/printers/install-batch', headers=auth_headers)
+    assert resp.status_code == 400