iris is the framework alone; the app is one crate in app-rust/

Iris: "the organization of the rust rewrite is a mess right now... there
shouldn't be anything related to the app inside of iris. Iris is supposed
to be the UI framework alone." And, on the crate count: "I'm confused why
the app only code needs more than one crate though."

Nine cargo workspaces become three, and the port's project code -- which
sat in five places, four of them inside the framework -- becomes one crate,
`ai-app`, in `app-rust/`:

  client-core                -> app-rust/src/client
  iris/transcript-ui         -> app-rust/src/ui
  iris/transcript-fixture    -> app-rust/src/ui/fixture.rs + tests/ + touch/
  iris/desktop-app           -> app-rust/src/desktop + src/bin_desktop.rs
  iris/android-app           -> app-rust/src/android + android-project/
  android-shell              -> app-rust/src/shell

iris/ keeps core, macro, the iris crate, tabs-ui and rig-input, and now
mentions no session, transcript, setup or server anywhere.

Only two of the old splits had a reason that survived reading. event-model
stays a crate at the repo root because server/ depends on it too, so a
crate is what makes the backend and the app agree by construction. The two
Android .so names looked like a hard constraint -- a package produces one
library artifact -- until P2 turned out to already plan merging those two
Android apps into one; both faces now come out of libai_app.so, picked
apart by features so `--no-default-features --features shell` keeps wgpu,
parley and iris out of the Compose app's APK. docs/RUST.md's "One app
crate" has the rest, including what each remaining feature is for.

DECISIONS.md and SUBAGENTS.md move into docs/ with everything else.

Verified: ./run-tests.sh and `cd iris && cargo test` green, clippy and fmt
clean in all five workspaces, `cargo ndk -t x86_64` links libai_app.so,
build-apk.sh produces an APK that installs and launches on this checkout's
emulator (Gl ... virgl, as expected), and the phone-sized headless
screenshot renders the transcript unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/androidApp/src/main/kotlin/com/example/aiapp/Api.kt

@@ -280,7 +280,7 @@ fun fetchSession(settings: ServerSettings, sessionId: String): SessionSummary =
  * One row of `GET /sessions/{id}/subagents`, oldest first.
  *
  * A subagent is a second transcript owned by a session -- no process, no controls of its own -- so
- * this carries only what a card needs to draw and to open it; see SUBAGENTS.md. [status] is
+ * this carries only what a card needs to draw and to open it; see docs/SUBAGENTS.md. [status] is
  * "running", "exited" or "unknown": a subagent whose session is not itself running cannot be
  * running, and the list says so rather than reporting a state that cannot hold.
  */

app/androidApp/src/main/kotlin/com/example/aiapp/AppRoot.kt

@@ -49,7 +49,7 @@ private sealed class Screen {
 
     /**
      * One subagent's own transcript, read-only. See [SessionScreen]'s `subagent` parameter and
-     * SUBAGENTS.md's "Phone". Closing it returns to [Main] under it, not to [Session]: a subagent
+     * docs/SUBAGENTS.md's "Phone". Closing it returns to [Main] under it, not to [Session]: a subagent
      * is opened from the session list's card rather than from inside the session it belongs to.
      */
     data class SubagentTarget(val summary: SessionSummary, val subagent: SubagentSummary)

app/androidApp/src/main/kotlin/com/example/aiapp/SessionListScreen.kt

@@ -478,7 +478,7 @@ private fun SubagentCard(subagent: SubagentSummary, onClick: () -> Unit) {
 }
 
 /**
- * The subcard's word for a subagent's status -- see SUBAGENTS.md's "Wire shape". Its own function
+ * The subcard's word for a subagent's status -- see docs/SUBAGENTS.md's "Wire shape". Its own function
  * rather than a branch inside [StatusText], because a subagent's three states are not that
  * composable's five: "exited" reads as "finished" here, since its process was always its parent's
  * and never something of its own to have merely stopped.

app/androidApp/src/main/kotlin/com/example/aiapp/TranscriptAddress.kt

@@ -5,7 +5,7 @@ package com.example.aiapp
  *
  * The single mechanism [fetchTranscript], [EventStream], [TranscriptSource] and
  * [TranscriptCache.session] all take, rather than each growing its own branch between a session and
- * a subagent -- see SUBAGENTS.md's "Phone" and "Wire shape". A caller that has only a session id
+ * a subagent -- see docs/SUBAGENTS.md's "Phone" and "Wire shape". A caller that has only a session id
  * builds one with the one-argument constructor; a subagent's screen supplies both ids.
  */
 data class TranscriptAddress(val sessionId: String, val subagentId: String? = null) {