feat(android): native mDNS discovery, host naming, touch mouse, stock selects

Discovery: replace the flaky per-OEM NsdManager with the same mdns-sd browse
the Linux/Windows clients use, in the Rust core over JNI and polled by Kotlin
(discovery.rs + nativeDiscovery{Start,Poll,Stop}); Kotlin keeps only the Wi-Fi
MulticastLock + permission UX. IPv4-only (the core can't dial a bare/scoped v6
literal); daemon + fold-thread cleanup on every failure path; field
sanitization so a rogue advert can't corrupt the picker snapshot. Discovery
now starts regardless of NEARBY_WIFI_DEVICES (raw multicast only needs the
MulticastLock) — a denial no longer kills it forever. ParseTxtTest replaced by
ParseRecordTest.

Hosts: hide already-saved hosts from the "Discovered" section (match by
fingerprint, else address:port — mirrors the Apple client); add an optional
Name field to the Add-host sheet and a Rename action on saved cards.

Input: touch -> absolute mouse "direct pointing" like the Apple client — the
host cursor follows the finger (new nativeSendPointerAbs -> MouseMoveAbs). Tap
= left click, two-finger tap = right click, two-finger drag = scroll,
tap-then-drag = left-drag, three-finger tap = HUD toggle.

Settings: revert the dropdowns to the stock ExposedDropdownMenuBox look (a
controller-focus UI will come separately); even out the Add-host field gaps.

Docs updated (CLAUDE.md, client READMEs, docs-site status).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/android/native/src/lib.rs

@@ -3,13 +3,17 @@
 //! Architecture: the **Rust-heavy** client model (like `punktfunk-client-linux`, *not* the
 //! thin-native-over-C-ABI Apple model). This `cdylib` links `punktfunk-core` directly and drives
 //! the whole `punktfunk/1` protocol through [`punktfunk_core::client::NativeClient`]; Kotlin owns
-//! only the Android-framework surface (Compose UI, `SurfaceView` lifecycle, input capture,
-//! `NsdManager` discovery, Keystore). The JNI seam below is the one place the two languages meet.
+//! only the Android-framework surface (Compose UI, `SurfaceView` lifecycle, input capture, the
+//! Wi-Fi `MulticastLock` + permission UX, Keystore). The JNI seam below is the one place the two
+//! languages meet.
 //!
 //! Why Rust-heavy: Kotlin cannot `import` the cbindgen C header the way Swift can, so a native
 //! bridge is unavoidable. Writing it in Rust lets the Android client reuse the Linux client's
 //! orchestration verbatim — audio jitter ring, the VK keymap inverse, latency/skew math, the
-//! input capture state machine, trust/pairing logic — instead of re-porting it into Kotlin.
+//! input capture state machine, trust/pairing logic, **mDNS discovery** ([`discovery`], the same
+//! `mdns-sd` browse the Linux/Windows clients use) — instead of re-porting it into Kotlin. Kotlin
+//! keeps only the Android-framework surface it must (Compose UI, `SurfaceView`, input capture, the
+//! Wi-Fi `MulticastLock` + permission UX, Keystore identity).
 //!
 //! JNI symbols map to `io.unom.punktfunk.kit.NativeBridge` in the `:kit` Gradle module
 //! (`clients/android`). The current surface is the scaffold's native-link proof
@@ -25,6 +29,9 @@ use jni::JNIEnv;
 mod audio;
 #[cfg(target_os = "android")]
 mod decode;
+// Ungated: pure `mdns-sd` + `jni`, so the browse + its JNI seam link into the host workspace build
+// (and its unit test runs there) exactly like `session`/`stats`. Kotlin only ever calls it on device.
+mod discovery;
 mod feedback;
 #[cfg(target_os = "android")]
 mod mic;