New web UI with iPhone web app

Redesigned status, log, tag generator and settings pages: spool rings in
filament colour, live job card (progress and time left read from CC2
Control's /api/printer while a job runs), log page with filters, iOS-style
settings with a write/dry-run switch. On phones: bottom tab bar, printer
switcher, slot details in a bottom sheet. Dark mode follows the system.
Web app manifest and home screen icons for "Add to Home Screen".

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

tools/mock_env.py

@@ -98,6 +98,13 @@ def make_cc2(host_header: str, P: dict) -> FastAPI:
             return {"available": True, "enabled": P["enabled"], "slots": P["slots"], "spools": P["spools"],
                     "job": P["job"], "log": P["log"]}
 
+    @app.get("/api/printer")
+    def printer_status():
+        active = P["job"]["active"]
+        return {"connected": True, "machine": {"status": 2 if active else 1, "progress": 42 if active else 0},
+                "print": {"filename": P["job"].get("file", ""), "state": "printing" if active else "standby",
+                          "current_layer": 23 if active else 0, "total_layers": 55, "remaining": 2940}}
+
     @app.get("/api/canvas")
     def canvas():
         return {"telemetry": {"result": {"canvas_info": {"canvas_list": [{"tray_list": [