Spool page for NFC links, bridge address; vendor-first new spool form

- /s/<id> shows a spool: rest in Spoolman and CC2 Control, where it is,
  last booking, history, links to Spoolman and the tag generator.
- Setting "Adresse der Bridge"; the tag generator can put <address>/s/<id>
  on the tag, so an iPhone held to the roll opens that page.
- New spool: vendor and material chosen from Spoolman, the vendor's
  filaments offered, values taken from similar filaments, duplicates
  pointed out and never created twice.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014GcEk5tkfFSYD6NTF66NkC

app/storage.py

@@ -122,6 +122,7 @@ class Settings:
     empty_grace: float = 20.0  # seconds with tray status 0 before a slot counts as empty
     settle_seconds: float = 60.0  # `remaining` must be unchanged this long before booking
     archive_empty: bool = True  # archive a Spoolman spool whose roll ran out
+    public_url: str = ""  # the bridge as phones reach it (links on NFC tags); empty: the address in the browser
     dry_run: bool = True
     printers: list[PrinterConfig] = field(default_factory=list)
 
@@ -162,6 +163,9 @@ class Settings:
         if not self.spoolman_url.startswith(("http://", "https://")):
             raise ValueError("Spoolman-URL muss mit http:// oder https:// beginnen")
         self.spoolman_url = self.spoolman_url.rstrip("/")
+        self.public_url = self.public_url.strip().rstrip("/")
+        if self.public_url and not re.fullmatch(r"https?://[^\s/?#]+(/[^\s?#]*)?", self.public_url):
+            raise ValueError("Adresse der Bridge muss mit http:// oder https:// beginnen, ohne ? oder #")
         if not self.location_storage.strip():
             raise ValueError("Ortsname für das Lager fehlt")
         ids = [p.id for p in self.printers]