Voice (dictate, read aloud) and Draw a picture over /v1, with the app's models scope

The server kept voice and images on /v1 (models scope, which the app's token
already asks for); /me's services and scopes decide what is offered. Rust
sends the recording to /v1/audio/transcriptions, reads /v1/audio/speech back
as a data: URL (CSP media-src data:), and for /v1/images/generations takes
only the id of each of the person's own files from the answer and fetches
/v1/files/<id>/content from the app's own server. The microphone is allowed
only within seconds of the page's own Dictate (voice_arm); WebKitGTK's
media stream is switched on through its settings getter.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src-tauri/Cargo.toml

@@ -32,6 +32,11 @@ tungstenite = { version = "0.30", default-features = false, features = ["handsha
 [target.'cfg(unix)'.dependencies]
 libc = "0.2"
 
+[target.'cfg(target_os = "linux")'.dependencies]
+# The webview's own settings: getUserMedia is off in WebKitGTK until the app turns it on.
+# The same crate and version wry already builds on.
+webkit2gtk = { version = "2.0", features = ["v2_4"] }
+
 [profile.release]
 codegen-units = 1
 lto = true