iris-android-app: keep the app's own log, put it in Copy report, upload it

`app_log` is the platform half: `android_logger` as the logger the ring
forwards to, and an optional destination baked in by `build.rs` from
`AI_APP_LOG_HOST`/`_PORT`/`_TOKEN` plus the pinned CA -- the same
build-time trust boundary the transcript config and the Compose APK's CA
already use, so no token is committed and an APK is good for the server
that built it. All three or none: two of the three would be a build with
nowhere to send its log and no way to say so.

`Copy report` now appends the ring to what goes on the clipboard (not to
the pane, which is on screen and would be buried) and flushes the
uploader first, so the lines are on the server by the time the message
describing them arrives. The Diagnostics pane gains two lines: how many
lines are held and when the last arrived, and what the uploader last did
-- "not tried yet", "failing -- <why>", and "no server configured" are
each their own wording, because "nothing is arriving" has three causes
that look identical otherwise.

Also: the re-emitted lines carry the target `ai_server::client_log`, not
a bare `client_log`. `RUST_LOG=ai_server=debug` -- the filter AGENTS.md
tells people to run with -- drops a bare target, so every line a phone
sent vanished with nothing saying so. Found by running it.

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

client-core/src/log_ring.rs

@@ -17,7 +17,7 @@
 //! the report, and a report taken twice must say the same thing.
 
 use std::collections::VecDeque;
-use std::sync::{Arc, Mutex};
+use std::sync::{Arc, Mutex, OnceLock};
 use std::time::{SystemTime, UNIX_EPOCH};
 
 /// How many lines a default ring holds, and how many bytes of message.
@@ -309,6 +309,37 @@ pub fn install(
     Ok(())
 }
 
+/// The one ring this process records into.
+///
+/// **A deliberate process-global, where this project's rules otherwise say
+/// pass context explicitly.** What is being modelled is already one: `log`
+/// has exactly one backend per process, set once, and every `log::info!`
+/// anywhere in the binary goes to it. A ring handed around as a parameter
+/// would be a *second* answer to "which lines exist" -- the report would
+/// show one ring while the logger filled another, and which one a caller
+/// got would depend on how far down the call tree it was. The tests above
+/// all use their own [`LogRing`], so nothing here needs this to be
+/// testable.
+static PROCESS_RING: OnceLock<LogRing> = OnceLock::new();
+
+/// The process's ring, created on first use with the default bounds.
+/// Safe to call before [`install_process_logger`] -- it will simply be
+/// empty.
+pub fn process_ring() -> &'static LogRing {
+    PROCESS_RING.get_or_init(LogRing::with_defaults)
+}
+
+/// Installs [`process_ring`] as the recording half of the process logger,
+/// forwarding to `inner` (the platform's own logger, already configured).
+/// The platform half of AGENTS.md's sharing rule is `inner`; everything
+/// else is shared.
+pub fn install_process_logger(
+    inner: Box<dyn log::Log>,
+    max_level: log::LevelFilter,
+) -> Result<(), log::SetLoggerError> {
+    install(process_ring().clone(), inner, max_level)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;