chore(android): port NeurophoneService Kotlin→Java JNI shim (#83)

[hyperpolymath]

Sub-PR #5 — Port NeurophoneService (Kotlin → Java JNI shim)

Part of the Android Kotlin→Rust/Gossamer migration: epic #83, RFC PR #97, sub-issue #111.

Draft / depends on unmerged work. Sub-PR #3 (Gossamer scaffolding) and #4 (NativeLib→Rust JNI in crates/neurophone-android) are being built in parallel and are not merged. This PR bases off main, assumes their structure, and marks integration seams TODO(#83 rebase).

What changed

• Removed android/app/src/main/java/ai/neurophone/NeurophoneService.kt (Kotlin foreground service that carried business logic + synthetic salience + widget publishing).
• Added android/app/src/main/java/ai/neurophone/NeurophoneService.java — a minimal hand-written Java Service shim. Same class name (ai.neurophone.NeurophoneService), so the existing BootReceiver.kt, widget/NeurophoneAppWidget.kt, and the AndroidManifest.xml .NeurophoneService entry resolve to it unchanged.

JNI calls used (NativeLib, Kotlin object → NativeLib.INSTANCE)

• onCreate() → NativeLib.init(null) then NativeLib.start()
• onDestroy() → NativeLib.stop()
• onSensorChanged() → NativeLib.processSensor(typeId, values, timestampNs, accuracy)

All JNI calls are wrapped in try/catch (Throwable) so dev hardware without the native lib still runs (matches prior Kotlin behaviour).

Convenience mapping replicated

Sensor type → compact id (mirrors the old NativeLib.pushSensorEvent table):

sensor	id
accelerometer	1
magnetometer	2
gyroscope	4
light	5
proximity	8
(else)	0

Timestamp converted ms → ns (System.currentTimeMillis() * 1_000_000L). Accuracy defaults to 3 (SENSOR_STATUS_ACCURACY_HIGH).

Kept thin (in scope)

Business logic stays in Rust. The shim keeps only the Android-owned concerns: foreground notification + channel, partial wake lock, and sensor registration (accelerometer only for now). Widgets / boot receiver / UI not ported.

Verification

• Diff touches only files under android/ (one Java add, one Kotlin delete). No Rust or Cargo.* files changed → cargo behaviour is identical to main.
• cargo build --workspace and cargo test --workspace fail on main already, in crates/lsm and crates/esn only (pre-existing rand 0.10 API drift: random()/sample() no longer resolve). This is unrelated to this PR and unaffected by it. The neurophone-android crate is an untouched stub and compiles.

TODOs / risks

• TODO(#83 rebase): NativeLib JNI signatures depend on sub-PR chore(deps): update thiserror requirement from 1.0 to 2.0 #4 landing the Rust exports (init/start/stop/processSensor).
• TODO(#83): widen sensor registration beyond accelerometer once the Rust core consumes the full set (the id mapping already covers them).
• TODO(#83): foreground notification / wake lock should migrate behind Gossamer/Rust, shrinking or removing this shim with the rest of android/.
• Risk: Java↔Kotlin-object interop uses NativeLib.INSTANCE; if chore(deps): update thiserror requirement from 1.0 to 2.0 #4 reimplements NativeLib as a Java class or changes the singleton shape, the call sites need a trivial rebase (flagged).

https://claude.ai/code/session_01Gu1JFCZHuBtBhAWPr4sMQw

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