feat: driver rename, driver icons, web image + driver search

Driver rename and icons: `Driver.display_name` plus a `DriverIcon` table, both
global/shared like the `Driver` row they hang off, so a rename or an icon is
what every Owner sees. The rename/icon dialog keeps its forms as siblings
(nested forms are invalid HTML) and the icon routes return an `hx-swap-oob`
thumbnail refresh rather than re-rendering the table, which would tear the open
`<dialog>` out of the DOM.

Web image picker: `GET /web/images` renders a pickable grid for a printer or a
driver icon, with the search term prefilled from the entity name and editable.
Picking one downloads it server-side and normalizes it.

Driver download search: `GET /web/drivers` searches for a vendor-wide driver
(the term is rewritten into the vendor's real product name for 15 brands) or for
the exact model as typed. Links only — nothing is downloaded, and the fragment
says the results are unvetted.

Icon uploads no longer reject off-size or non-PNG files: `normalize_icon()`
letterboxes any decodable raster into a 256x256 PNG. An already-exact 256x256
PNG is returned byte-identical, because icon storage is content-addressed and
re-encoding would move the file on every save.

`fetch_image()` makes the request from the server, so `assert_fetchable()`
refuses any URL resolving to a private, loopback, or link-local address, and
re-runs on every redirect. ImpTune sits on the same LAN as the printers it
configures; an unguarded fetcher would be a port scanner for anyone who can
reach the UI.

DuckDuckGo is scraped, not called through an API — no key needed, but fragile,
so both search functions swallow parse failures and return [] instead of 500ing
a page. `WEB_SEARCH=false` disables every outbound request and hides the
controls, for air-gapped installs.

Also: one shared `Jinja2Templates` in `templating.py` instead of five per-router
instances, so a template global is declared once; `_add_missing_columns()` in
`database.py` adds new nullable columns to a pre-existing table, which
`create_tables(safe=True)` skips; `db_env` in test_db.py now closes its
connection on teardown, or the next test's ORM writes land in the previous
test's DB file.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

imptune/api/pages.py

@@ -1,17 +1,14 @@
 import json
 from collections import defaultdict
-from pathlib import Path
 
 from fastapi import APIRouter, Request
 from fastapi.responses import HTMLResponse
-from fastapi.templating import Jinja2Templates
 from peewee import JOIN, fn
 
+from imptune.templating import templates
 
 router = APIRouter()
 
-templates = Jinja2Templates(directory=str(Path(__file__).parent.parent / "templates"))
-
 # Group label for printers with no client — the template translates it.
 UNASSIGNED_GROUP = "Unassigned"
 
@@ -57,12 +54,31 @@ def group_printers_by_client(printers) -> dict[str, list]:
     return ordered
 
 
-def _driver_data(drivers) -> list[dict]:
-    """Attach the parsed driver names to each Driver row for template use."""
-    return [
-        {"driver": d, "names": json.loads(d.driver_desc) if d.driver_desc else []}
-        for d in drivers
-    ]
+def build_driver_data(drivers) -> list[dict]:
+    """Attach parsed driver names + icon presence to each Driver row.
+
+    Shared by every template that lists drivers (library table, printer form
+    select, edit modal) so a rename or a new icon shows up in all of them.
+    """
+    from imptune.services.icons import driver_icon_ids, driver_search_text
+    from imptune.services.websearch import image_query
+
+    drivers = list(drivers)
+    with_icons = driver_icon_ids(drivers)
+    data = []
+    for d in drivers:
+        names = json.loads(d.driver_desc) if d.driver_desc else []
+        search_text = driver_search_text(d, names)
+        data.append(
+            {
+                "driver": d,
+                "names": names,
+                "has_icon": d.id in with_icons,
+                "search_text": search_text,
+                "image_query": image_query(search_text),
+            }
+        )
+    return data
 
 
 @router.get("/", response_class=HTMLResponse)
@@ -109,13 +125,16 @@ def dashboard(request: Request):
 def drivers_page(request: Request):
     from imptune.db.models import Driver
 
+    from imptune.services.websearch import BRAND_SUGGESTIONS
+
     drivers = list(Driver.select().order_by(Driver.uploaded_at.desc()))
     return templates.TemplateResponse(
         request=request,
         name="drivers.html",
         context={
-            "driver_data": _driver_data(drivers),
+            "driver_data": build_driver_data(drivers),
             "usage": printer_counts_by_driver(request.state.owner),
+            "brands": BRAND_SUGGESTIONS,
         },
     )
 
@@ -145,7 +164,7 @@ def printers_page(request: Request):
         context={
             "grouped": grouped,
             "clients": clients,
-            "driver_data": _driver_data(all_drivers),
+            "driver_data": build_driver_data(all_drivers),
             "printer_count": printer_count,
             "ready_count": ready_count,
         },
@@ -161,13 +180,14 @@ def printers_new_page(request: Request):
     return templates.TemplateResponse(
         request=request,
         name="printers_new.html",
-        context={"clients": clients, "driver_data": _driver_data(all_drivers)},
+        context={"clients": clients, "driver_data": build_driver_data(all_drivers)},
     )
 
 
 @router.get("/printers/{printer_id}", response_class=HTMLResponse)
 def printer_detail(request: Request, printer_id: int):
     from imptune.db.models import Client, Driver, Icon, Printer
+    from imptune.services.websearch import image_query
 
     printer = (
         Printer.select(Printer, Client, Driver)
@@ -201,6 +221,7 @@ def printer_detail(request: Request, printer_id: int):
             "driver_names": driver_names,
             "has_driver": has_driver,
             "has_icon": icon is not None,
+            "image_query": image_query(printer.name),
             "install_cmd": install_cmd,
             "uninstall_cmd": uninstall_cmd,
         },
@@ -251,7 +272,7 @@ def client_detail(request: Request, client_id: int):
             "client": client,
             "grouped": grouped,
             "clients": clients,
-            "driver_data": _driver_data(all_drivers),
+            "driver_data": build_driver_data(all_drivers),
             "printer_count": len(printers),
             "ready_count": sum(1 for p in printers if p.driver_id),
         },