chore: trim unnecessary Arti features to reduce binary size

- Set default-features = false on arti-client and tor-rtcompat
- Removed bridge-client (UI doesn't expose bridge config yet)
- Narrowed tokio features from "full" to only what the SOCKS proxy
  needs: rt-multi-thread, net, io-util, time, macros

Kept: tokio, rustls, compression, onion-service-client, static-sqlite
(all required for Amethyst's .onion relay support)

https://claude.ai/code/session_01BApgDd5udqBzMqysSRMpZu

tools/arti-build/Cargo.toml

@@ -9,17 +9,16 @@ crate-type = ["cdylib"]
 [workspace]
 
 [dependencies]
-arti-client = { version = "0.38", features = [
+arti-client = { version = "0.38", default-features = false, features = [
     "tokio",
     "rustls",
     "compression",
-    "bridge-client",
     "onion-service-client",
     "static-sqlite",
 ] }
-tor-rtcompat = { version = "0.38", features = ["tokio", "rustls"] }
+tor-rtcompat = { version = "0.38", default-features = false, features = ["tokio", "rustls"] }
 jni = "0.21"
-tokio = { version = "1", features = ["full"] }
+tokio = { version = "1", features = ["rt-multi-thread", "net", "io-util", "time", "macros"] }
 anyhow = "1"
 
 [profile.release]

tools/arti-build/README.md

@@ -148,14 +148,24 @@ The Rust wrapper (`src/lib.rs`) exposes these JNI functions to Kotlin:
 
 ## Cargo.toml features
 
-| Feature | Purpose |
+Default features are disabled (`default-features = false`) to minimize binary size.
+
+| Feature | Purpose | Why included |
+|---|---|---|
+| `tokio` | Async runtime | Required by our SOCKS proxy |
+| `rustls` | TLS via pure Rust | No OpenSSL dependency, smaller binary |
+| `compression` | zstd/deflate relay traffic | Reduces bandwidth on Tor circuits |
+| `onion-service-client` | Access .onion addresses | Amethyst routes .onion relay connections through Tor |
+| `static-sqlite` | Bundled SQLite | Android native code can't use system SQLite |
+
+**Not included:**
+
+| Feature | Why excluded |
 |---|---|
-| `tokio` | Async runtime |
-| `rustls` | TLS without OpenSSL (smaller, no system dependency) |
-| `compression` | Tor relay compression support |
-| `bridge-client` | Connect via Tor bridges |
-| `onion-service-client` | Access .onion addresses |
-| `static-sqlite` | Bundled SQLite for state storage |
+| `native-tls` | Using `rustls` instead (smaller, no system dependency) |
+| `bridge-client` | Amethyst doesn't expose bridge configuration in UI yet. Add back if needed. |
+| `pt-client` | Pluggable transports — same reason as bridges |
+| `onion-service-service` | We only connect to .onion, we don't host them |
 
 ### Release profile