v0.1.0-U (vc=8): Phase U-1 + U-2 — Rust core + rustypipe search

NewPipeExtractor (Java) → strawcore (Rust) migration begins. Phase U:
- U-1: Rust toolchain + UniFFI smoke test
- U-2: rustypipe search via uniffi suspend fun, SearchViewModel swapped

What landed:
- rust/strawcore — UniFFI-exported Rust crate using proc-macros.
  Builds for arm64-v8a + armeabi-v7a + x86 + x86_64 via cargo-ndk.
  Tokio multi-thread runtime singleton drives rustypipe's async API.
- strawApp/build.gradle.kts — cargoBuildHost + cargoBuild + uniffiBindgen
  Gradle Exec tasks chained into the Android build. Generated Kotlin
  bindings land in src/main/java/uniffi/strawcore/ (gitignored).
- SearchViewModel.kt — calls uniffi.strawcore.search(query) directly.
  NewPipeExtractor still in deps for VideoDetail/Player/Channel paths;
  those move to Rust in U-3 / U-4.
- Build chain quirks beat:
  * cargo absolute path in Exec tasks (PATH wasn't propagating)
  * uniffi-bindgen needs UNSTRIPPED host .so — separate cargoBuildHost
    builds a debug-profile host lib to read metadata from
  * rustypipe rustls-tls-webpki-roots avoids the openssl-sys
    cross-compile tarpit
  * rquickjs-sys 'bindgen' feature opted in (no prebuilt Android
    bindings ship; build-host has libclang 14)
- build-host runtime install (until Dockerfile catches up):
  rustup + 4 Android targets + cargo-ndk + NDK r27c. Persists in
  /caches/cargo + /caches/android-sdk via the volume mount.

APK size: 22MB (U-1) → 37MB (U-2). libstrawcore.so 3-5MB per ABI carries
rustypipe + reqwest + tokio + rustls + rquickjs. NewPipeExtractor still
in for now (still drives detail + player + channel + feed), so the
Java half is doubled up. U-5 removes it.

rust/strawcore/src/lib.rs

@@ -0,0 +1,46 @@
+// strawcore — Rust core for the Straw Android app.
+//
+// Phase U-1: hello-world smoke test. One exported function, returns a
+// String so we know JNI + UniFFI marshalling works end-to-end before we
+// pull in rustypipe.
+//
+// Phase U-2+ adds real APIs (search, stream_info, channel_info).
+
+use std::sync::Once;
+
+mod error;
+mod runtime;
+mod search;
+
+#[allow(unused_imports)]
+use runtime::block_on;
+
+// Re-exports so UniFFI sees the types at the crate root for macro discovery.
+pub use error::StrawcoreError;
+pub use search::SearchItem;
+
+/// Initialize Android logging once. The Kotlin side calls this from
+/// StrawApp.onCreate() so anything emitted via `log::info!()` shows up in
+/// `adb logcat -s strawcore`.
+#[uniffi::export]
+pub fn init_logging() {
+    static ONCE: Once = Once::new();
+    ONCE.call_once(|| {
+        android_logger::init_once(
+            android_logger::Config::default()
+                .with_max_level(log::LevelFilter::Info)
+                .with_tag("strawcore"),
+        );
+        log::info!("strawcore initialized");
+    });
+}
+
+/// Smoke-test entry point — round-trip a string through JNI so we know
+/// the bridge is working before pulling in rustypipe.
+#[uniffi::export]
+pub fn hello_from_rust(name: String) -> String {
+    log::info!("hello_from_rust called with name={}", name);
+    format!("hello {} from rust 🦀 (strawcore v{})", name, env!("CARGO_PKG_VERSION"))
+}
+
+uniffi::setup_scaffolding!();