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.

strawApp/build.gradle.kts

@@ -110,4 +110,98 @@ dependencies {
     implementation("androidx.media3:media3-session:1.4.1")
     // Guava ListenableFuture support for awaiting MediaController connect.
     implementation("androidx.concurrent:concurrent-futures-ktx:1.2.0")
+
+    // strawcore — Rust YouTube extractor via UniFFI/JNA. Built by the
+    // cargoBuild + uniffiBindgen tasks below; phase U-2+ exposes search /
+    // streamInfo / channelInfo to replace NewPipeExtractor.
+    implementation("net.java.dev.jna:jna:5.14.0@aar")
 }
+
+// =============================================================================
+// Phase U-1 — Rust core build glue.
+//
+// Two tasks chain into the Android build:
+//   cargoBuild       — cross-compiles rust/strawcore for the four Android ABIs
+//                      via cargo-ndk and drops the .so files in strawApp/src/main/jniLibs/.
+//   uniffiBindgen    — generates the Kotlin bindings from the freshly-built lib
+//                      into strawApp/src/main/java/uniffi/strawcore/.
+//
+// Both depend on:
+//   - cargo + rustup with the four Android targets installed
+//   - cargo-ndk on PATH
+//   - ANDROID_NDK_HOME pointing at an NDK with the right toolchains
+// All of that lives in the build-host container (see internal-infra
+// containers/build-host/Dockerfile + ad-hoc install notes 2026-05-24).
+// =============================================================================
+
+val rustRoot = file("../rust").absolutePath
+val jniLibsDir = file("src/main/jniLibs").absolutePath
+val bindingsDir = file("src/main/java").absolutePath
+
+// Resolve cargo + the NDK by absolute path so the Gradle Exec tasks don't
+// depend on whatever PATH the user invoked gradle with. Fall back to env
+// var (CARGO_HOME) if set, else the build-host default.
+val cargoHome: String = System.getenv("CARGO_HOME") ?: "/caches/cargo"
+val cargoBin: String = "$cargoHome/bin/cargo"
+val ndkHome: String = System.getenv("ANDROID_NDK_HOME")
+    ?: System.getenv("ANDROID_NDK_ROOT")
+    ?: "/caches/android-sdk/ndk/27.2.12479018"
+
+val cargoBuild by tasks.registering(Exec::class) {
+    group = "rust"
+    description = "Cross-compile strawcore for all Android ABIs via cargo-ndk."
+    workingDir = file(rustRoot)
+    environment("ANDROID_NDK_HOME", ndkHome)
+    environment("PATH", "$cargoHome/bin:${System.getenv("PATH") ?: ""}")
+    commandLine = listOf(
+        cargoBin, "ndk",
+        "-t", "arm64-v8a",
+        "-t", "armeabi-v7a",
+        "-t", "x86",
+        "-t", "x86_64",
+        "-o", jniLibsDir,
+        "build", "--release", "-p", "strawcore",
+    )
+    standardOutput = System.out
+    errorOutput = System.err
+}
+
+// Build a host-arch debug .so for uniffi-bindgen to read metadata from.
+// Cross-compiled Android .so files have the same UniFFI metadata symbols,
+// but the release profile's strip+LTO can strip the sections in a way that
+// trips bindgen's library-mode reader. Build host debug separately.
+val cargoBuildHost by tasks.registering(Exec::class) {
+    group = "rust"
+    description = "Build host-arch debug strawcore so bindgen can read its UniFFI metadata."
+    workingDir = file(rustRoot)
+    environment("PATH", "$cargoHome/bin:${System.getenv("PATH") ?: ""}")
+    commandLine = listOf(cargoBin, "build", "-p", "strawcore")
+    standardOutput = System.out
+    errorOutput = System.err
+}
+
+val uniffiBindgen by tasks.registering(Exec::class) {
+    group = "rust"
+    description = "Generate Kotlin bindings for strawcore via uniffi-bindgen."
+    dependsOn(cargoBuildHost)
+    workingDir = file(rustRoot)
+    environment("PATH", "$cargoHome/bin:${System.getenv("PATH") ?: ""}")
+    commandLine = listOf(
+        cargoBin, "run", "--quiet", "--bin", "uniffi-bindgen", "--",
+        "generate",
+        "--library", "target/debug/libstrawcore.so",
+        "--crate", "strawcore",
+        "--language", "kotlin",
+        "--no-format",
+        "--out-dir", bindingsDir,
+    )
+    standardOutput = System.out
+    errorOutput = System.err
+}
+
+// Make sure Android's JNI-libs merge picks up the freshly built .so files,
+// and Kotlin compilation can resolve the generated bindings.
+tasks.matching { it.name.startsWith("merge") && it.name.endsWith("JniLibFolders") }
+    .configureEach { dependsOn(cargoBuild) }
+tasks.matching { it.name.startsWith("compile") && it.name.endsWith("Kotlin") }
+    .configureEach { dependsOn(uniffiBindgen) }