[tiensonqin]

Keep the code language selector as a small, untranslated caption inside the code container, so “Plain text” and “calc” no longer appear as separate prose rows. Code, Calculator and Math use Enter to create a plain sibling block and Shift+Enter for a line break.

• Render Calculator expressions on the left and live per-line results on the right, using the shared OCaml evaluator and the unsaved editor draft, including variables and last.
• Restore long-press block selection over code and math previews, and preserve ordinary text/math previews when code content or editors mount and unmount.
• Cover master-compatible slash-command behavior through both clicking and Enter: clear the slash and typed query, preserve surrounding Unicode text, and insert code/calculator after nonempty content.
• Keep code containers at their content height on Android and share the layout in OCaml.

Validation:

• Full OCaml core gate: 1183 tests passed. The remote ocaml-core CI check also passed.
• iOS 26 simulator build and native checks passed: Enter/Shift+Enter, UTF-16 selections and delayed caret acknowledgements, ordinary text/code/math preview mounting, actual formula rendering, and code-to-plain-block keyboard focus. Calculator live results and code/math long-press selection were also exercised in the simulator.
• Android debug build and emulator checks passed: 19 rich-content interaction tests, 8 code/math rendering tests, and the real-core Calculator integration covering live results, horizontal layout, exactly one new block on IME Enter, and long-press selection.
• Remote iOS E2E bootstrap stops before compiling the app because its cached opam switch requires ocaml-base-compiler.5.5.2, which is no longer available.

Recordings use the same offline fixture on the iOS 26 simulator. Video files and diagnostic logs are excluded from the commit.

Before — main 59154a47: detached language label, no live result column, and Enter stays in the code block.

before-calculator-main-comparison.mp4

After — 3029ce41: compact language selector inside the container, live results (42 and 126), Shift+Enter newline, Enter creates a sibling, and long-press block selection.

after-calculator-3029ce41.mp4