Perf/optimizations

[cesp99]

Summary

Cuts the native library from 41 MB to 23.5 MB per ABI (−43%; arm64 APK 37 → 10.6 MB) and removes the
main runtime hot-spots: per-keystroke JNI window re-marshaling, whole-subtree recompositions, always-on
background polling, and redundant git runs under proot. Also adds a committed baseline profile so cold
start runs AOT-compiled code.

Type of change

• Bug fix
• New feature
• Performance improvement
• Refactor / cleanup
• Documentation
• Build / CI
• Other

Architecture & conventions checklist

• Editor logic stays in Rust (core/); UI/platform stays in Kotlin (app/)
• No Android types leaked into Rust, no editor logic in Kotlin
• If the JNI boundary changed, both core/crates/jni-bridge/src/lib.rs and app/…/core/CoreBridge.kt were updated together
• No blocking calls on the main thread; no per-keystroke JNI chatter
• No telemetry, analytics, or network calls the user didn't ask for
• Interactive features ship touch and keyboard and mouse support
• docs/SHORTCUTS.md updated if new shortcuts/commands were added
• No private info (personal emails, keys, machine paths) in committed files
• Code copied/adapted from elsewhere is GPL-3.0-compatible and attributed

Edition impact

• full (Debian userland, apt, F-Droid/direct APK)
• play (Play-compatible, no userland)
• Both equally
• Neither (docs / tooling only)

Testing

• ./gradlew assembleFullDebug assemblePlayDebug
• cd core && cargo test
• cd core && cargo clippy
• Tested on a real device (specify model / form factor below)
• Tested on the foldable emulator (tools/fold-emulator.sh)

Device tested on (if applicable):

Samsung Galaxy Fold 8 Ultra (outer and inner screen)

Notes: engine suite is 271 tests (new coverage for the window cache, cached HEAD/branch reads, and ACP
version counters). cargo clippy exits clean; three warning sites remain in project.rs/highlight.rs
that pre-exist on main. One pre-existing LSP-budget test flakes under full parallel load only.
Baseline profile was generated on a headless Gradle-managed device (pixel6Api36), not the foldable
emulator. Behavior notes for review: panic = "abort" now ends the process on an engine panic (logcat
message first), and gpui's image/SVG decoding is behind an off-by-default feature (Compose does all real
media rendering).

Screenshots / recordings

No visual changes, title bar (branch + drift arrows), terminal theming, and editor rendering are
pixel-identical by design.

Related issues

none

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