The app hands its log to Dev Updater on the phone, not through ai-server

Iris's call once the upload route was working: put it in Dev Updater
properly. So the app now exposes its own ring through a ContentProvider
at `<applicationId>.devlog` -- Dev Updater's contract, written down in
that project's README, not something invented here -- and Dev Updater's
phone app reads it on the same device and forwards it to its own build
machine. No tunnel, no token, no second enrolment, and any app that
server delivers can implement the same and get the same Runtime tab.

`DevLogProvider.java` plus `devlog.rs` are the platform glue only: a flat
`String[]` across JNI, a `MatrixCursor` on the Java side, and
`nativeReady` telling Rust the authority the provider actually
registered, so the Diagnostics pane can name somewhere a reader can
query rather than composing a guess. `LogRing::newest_seq()` is the one
addition in `client-core`: an in-memory ring starts again at zero, so it
is what lets a reader notice the process restarted instead of silently
skipping everything since.

Deleted with it, so there is one mechanism: `client_core::log_upload`,
`POST /client-log` on ai-server, the `AI_APP_LOG_*` baking (which left
`build.rs` with nothing to do), and the uploader on both Android
clients. Kept: the ring, `RingLogger`, `install_process_logger`, and the
Diagnostics line -- whose second half is now `devlog provider:
content://<authority>`.

Verified end to end on this checkout's emulator: iris's own
`iris::android::view` startup lines read out of the provider by the
shell, forwarded by Dev Updater's Runtime tab, and served back from
`GET /apps/android-app/components/app/logs?kind=runtime`. A component
whose package has no provider says so in as many words.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

client-core/src/lib.rs

@@ -9,7 +9,6 @@ pub mod durations;
 pub mod event_stream;
 pub mod highlight;
 pub mod log_ring;
-pub mod log_upload;
 pub mod markdown_blocks;
 pub mod notifications;
 pub mod sse;