v1.1.0: stable Gemini voice, faster networking

• Wi-Fi receive no longer starves: received frames are copied out of the
  driver's buffers (LWIP_L2_TO_L3_COPY). With audio running, LAN 1.6-2.2
  MB/s (was 143-480 KB/s) and HTTPS ~450 KB/s with no pauses; Gemini
  replies arrive faster than real time without underruns.
• A song's download is held during an assistant session.
• 32 KB TCP receive window in the defaults.
• Wi-Fi fixes: setup AP turns off after a credentials change; re-applying
  the current network reconnects; the configure reply is not cut off.
• USB port can act as a network adapter (usb-mode).
• Diagnostics: nettest (download/upload, pauses, IP precedence, lwIP
  drops), wifi-sniff radio capture, wifi-log, wifi-rx, wifi-mac, and
  experiment flags from /sdcard/tuning.json (/api/system/tuning).
• Known issue: some routers cap ISP-marked traffic at ~85 KB/s
  (esp-idf#19168).