RUST.md: client-core is built; IRIS_TODO.md committed

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

RUST.md

@@ -84,10 +84,12 @@ session spending an afternoon on them again.
   what stands in for that until I2 gets a device.
 - **Next**: **I2** — iris on android-view. **E2** (a transcript in
   Masonry) can go in parallel in another session.
-- **Not started**: `client-core`, which is item 1 of the recommendation
-  below and does not depend on the framework choice. Nothing has been
-  built for it, and it is not one of the numbered boxes — worth picking up
-  in a session that wants work independent of the emulator.
+- **`client-core` built (2026-09-04)**, item 1 of the recommendation:
+  `event-model/` (the event types, now shared with `server/`) and
+  `client-core/` (REST and SSE clients, transcript fold, cache, highlighter,
+  ANSI parser, 85 ported tests). `CLIENT_CORE.md` maps Kotlin file to Rust
+  module and lists what is not yet covered. `./run-tests.sh` runs all three
+  crates.
 - **The app itself is untouched.** Everything so far is in `iris/`, in
   `rigs/gpu-probe` (a headless wgpu/Vulkan feature probe, pushable to a
   device with no APK — see the binding-array section), and in the other
@@ -487,7 +489,7 @@ light" has a knob inside the same stack.
 
 ## Recommendation
 
-1. **Build `client-core` now, whatever the framework.** A Rust crate holding
+1. **Build `client-core` now, whatever the framework** (done 2026-09-04, see `CLIENT_CORE.md`). A Rust crate holding
    the event model (shared with `server/` as one crate, ending the
    `Events.kt` mirror), the API and SSE clients, the transcript fold, the
    cache, the markdown block model, the highlighter and the ANSI parser,