redbear-iwlwifi: add Wi-Fi IP datapath bridge

Phase 3 of the systematic networking plan.

The bridge lives entirely in the redbear-iwlwifi recipe. It
exposes a network.wlan0 scheme on top of the existing iwlwifi
control plane, so netstack treats it as a normal Ethernet
device without any change to netstack itself.

Components (all in local/recipes/drivers/redbear-iwlwifi):

- src/bridge/mod.rs (15 KB): WifiLinkBridge struct, RX/TX
  state, BSSID, mac state, stats, associated flag. All
  state behind Arc<Mutex<>> for safe sharing with the
  scheme handler thread.
- src/bridge/convert.rs (26 KB): wifi_to_ethernet() and
  ethernet_to_wifi() pure functions. All four ToDS/FromDS
  addressing modes, full LLC/SNAP detection (handles
  both AA-AA-03-00-00-00 framing and the Linux 4-2
  stripped form), and a complete round-trip test
  suite.
- src/bridge/callback.rs (11 KB): the unsafe extern C
  callback that ieee80211_rx_drain calls. Drops
  kernel-injected management frames and passes
  filtered data frames through convert.rs.
- src/bridge/scheme.rs (16 KB): the Redox scheme handler.
  Registers network.wlan0 with read/write/handles.
  Read drains the bridge RX queue; write calls
  ethernet_to_wifi then iwl_ops_tx_skb.

linux_port.c additions:
- rb_iwlwifi_bridge_register_rx(hw) is invoked from
  rb_iwlwifi_register_mac80211_locked after
  ieee80211_register_hw, registering bridge_rx_callback
  as the RX handler.
- rb_iwlwifi_bridge_tx_submit(data, len) wraps a frame
  in an sk_buff and calls iwl_ops_tx_skb.
- rb_iwlwifi_bridge_hw keeps a single static
  ieee80211_hw* for the callback dispatch.

main.rs changes:
- The --daemon path now initializes the bridge after
  full_init, hands it to the bridge module, and runs
  bridge::scheme::run_event_loop. The previous
  'loop { sleep(3600); }' is gone.

Verification contract built into the bridge modules:
- convert.rs: all 4 ToDS/FromDS modes, LLC/SNAP
  presence/absence, IPv4/IPv6/ARP payloads, round-trip
  preservation.
- mod.rs: push/pop/activate/deactivate state machine.
- scheme.rs: scheme read/write handshake with mock
  driver backend.

Netstack impact: zero. The netcfg scheme already
discovers network.* and creates EthernetLink on
top; wlan0 looks identical to netstack.

NOT yet validated on real hardware (Phase 6 deferred
to hardware acquisition). Hardware validation will
require a real Intel BE201/BE200 NIC and an AP with
known credentials.

local/recipes/system/evdevd/source/src/main.rs

@@ -136,7 +136,39 @@ fn dispatch_input_event(event: Event, scheme: &mut EvdevScheme) {
             scheme.feed_mouse_buttons(button.left, button.middle, button.right)
         }
         EventOption::Scroll(scroll) => scheme.feed_mouse_scroll(scroll.x, scroll.y),
-        _ => {}
+
+        // orbclient "no event" sentinel — not a real event, ignore silently.
+        EventOption::None => {}
+
+        // Unrecognised event code from the input scheme. This is operationally
+        // anomalous (the input scheme should only emit codes orbclient knows),
+        // so surface it at warn for operator visibility.
+        EventOption::Unknown(unknown) => {
+            let (code, a, b) = (unknown.code, unknown.a, unknown.b);
+            log::warn!(
+                "evdevd: dropping unknown input event (code={} a={} b={}); no evdev mapping",
+                code,
+                a,
+                b
+            );
+        }
+
+        // Remaining variants (TextInput, Quit, Focus, Move, Resize, Screen,
+        // Clipboard, ClipboardUpdate, Drop, Hover) are orbclient window-system
+        // events with no evdev equivalent: evdev is a raw input-device protocol
+        // carrying scancodes, axes, and button state, while composed text,
+        // window lifecycle, and clipboard handling are compositor-level
+        // concerns that live above this daemon. They are not produced by
+        // /scheme/input/consumer_raw in practice; if one ever appears we log
+        // at debug so operators can trace the stream without flooding the
+        // default log level.
+        other => {
+            log::debug!(
+                "evdevd: ignoring non-device {:?} event; evdev forwards only \
+                 key/mouse/button/scroll events",
+                other
+            );
+        }
     }
 }