Add docs/app-split-recipes.md; update the handoff to 78 left

Dart's library-scoped privates (use part/part of), Kotlin's lack of any
equivalent (use an internal fixture object), and the TypeScript seams
that compile clean and fail at runtime - three projects hit that last
one. Also the per-project test baselines, including that gradle prints
UP-TO-DATE rather than a count and needs JDK 21 pinned.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011w2Pj4Ek3ZNMQVYcFHgXDY

docs/app-split-recipes.md

@@ -0,0 +1,78 @@
+# App split recipes (Dart, Kotlin, TypeScript)
+
+Settled while clearing `focus_owner`, `kcd2_dice_solver` and
+`reverse_survivors`. Referenced from `refactor_claude_todo_resume.md`.
+
+## Baselines — measure before editing, re-check after
+
+| Project                | Command             | Expect         |
+| ---------------------- | ------------------- | -------------- |
+| `focus_owner` (Dart)   | `flutter test`      | 94             |
+| `focus_owner` (Kotlin) | see below           | 40, 0 failures |
+| `kcd2_dice_solver`     | `npm test -- --run` | 288            |
+| `reverse_survivors`    | `npm test -- --run` | 160            |
+
+Gradle prints `UP-TO-DATE` rather than a count, so read the JUnit XML, and
+**pin the JDK** — the default JDK 26 breaks the AGP jlink transform:
+
+```bash
+cd focus_owner/android
+JAVA_HOME=/usr/lib/jvm/java-21-openjdk ./gradlew testDebugUnitTest --offline
+grep -ho 'tests="[0-9]*"' ../build/app/test-results/testDebugUnitTest/*.xml \
+  | grep -oP '\d+' | paste -sd+ | bc
+```
+
+## Dart: privates are library-scoped, so use `part`
+
+A separate file is a separate **library**, so `_Card` and friends are invisible
+to it. Splitting `main.dart` with `import` + `export` produced 30 errors of the
+form "The name `_Card` isn't a class". `part 'x.dart';` + `part of 'main.dart';`
+keeps both files in one library and the analyzer goes straight to zero issues.
+
+The part file carries **no imports of its own** — it inherits the library's.
+
+**A `part` cannot rescue a State class.** `status_page_state.dart` stayed over
+the cap: its methods call `setState` and read seven private fields, and a
+`mixin on State<...>` cannot see them without declaring the state twice.
+
+**Splitting a widget test off its `testWidgets` group loses the binding.**
+Four tests failed with "Binding has not yet been initialized" because the
+group that had been initialising it implicitly moved away. Add
+`TestWidgetsFlutterBinding.ensureInitialized()` to **both** halves.
+
+## Kotlin: no `part`, so use an internal fixture object
+
+Shared `private val`/`private fun` test fixtures go into an
+`internal object XFixtures` in the same package, and each test class delegates
+to it. Two compile failures came from missing one (`installed`) — list every
+`private` member of the original class before cutting.
+
+`EnforcementRunner.kt` is **not splittable** as it stands: its location block
+reads the private constructor property `context` and `prefs()` eleven times,
+which no extension function can reach.
+
+## TypeScript: `tsc` does not tell you a split worked
+
+Three separate projects had a seam that compiled clean and failed at runtime:
+
+- an import cycle leaves a constant `undefined` at module-init
+  (`HEADSTART_POINTS`, twice, in `kcd2`);
+- a moved function is simply not there (`survivorStep`, 63 failures);
+- a type name that collides with a DOM global resolves to the DOM one — the
+  error talks about `anchorNode` rather than saying the name is missing.
+
+**Always run the suite.** Prune the imports the split leaves behind by
+iterating on `tsc`'s own TS6133/TS6192/TS6196 output rather than guessing, but
+note it cannot see a helper another file still needs.
+
+## Coverage: new files must land inside the include glob
+
+`kcd2` and `reverse_survivors` both gate at 100%. New source modules are picked
+up automatically; **shared test fixtures must go in `src/test/`**, which the
+coverage `exclude` names by path. Beside the source they count as production
+code and break the gate — the same trap recorded for `poker-stakes`.
+
+## A split that empties a file must delete it
+
+`App.test.tsx` lost its last `describe` and vitest failed the whole run with
+"No test suite found in file". Remove the shell.

refactor_claude_todo_resume.md

@@ -6,8 +6,9 @@
 
 ## Where things stand
 
-**83 files** over 250 lines (was 183). Everything is committed and pushed to
-`main` at `093e2f6`; the tree is clean.
+**78 files** over 250 lines (was 183). Everything is committed and pushed to
+`main` at `2ce86a5`. `focus_owner/analysis_options.yaml` has an uncommitted
+change from an earlier session — **leave it unstaged**, it is not ours.
 
 **`python_pkg/` is DONE — 50 violations → 0.** Do not reopen it. Cleared one
 package per tranche, pushing after each: `brother_printer` (15→0, suite pinned
@@ -62,8 +63,12 @@ Same in TypeScript: `kcd2`'s `search.ts` and `badgeValue.ts`, and
 caller's globals — stricter than `shellcheck -x` on the entry, and the check
 that decides whether a seam is real. Run it before believing a split.
 
-Next: the remaining `main()`-shaped shell scripts, then `focus_owner` and
-`billsplit` (Kotlin+Dart, untouched so far — check for a test command first).
+Next: `billsplit` (Dart, untouched), then the remaining `main()`-shaped shell
+scripts. `focus_owner`'s six leftovers are four Kotlin sources that read a
+private `context`, one State class, and one test one line over.
+
+Baselines and the per-language traps (Dart `part`, Kotlin fixture objects, the
+TS import cycle) are in `docs/app-split-recipes.md`.
 
 ## The live worklist
 
@@ -136,10 +141,12 @@ Plus `.github/workflows/file-length.yml` modelled on
 
 ## Language recipes
 
-- `docs/python-split-recipes.md` — the seam-selection rule, the `__all__`
-  re-export form, the `TC001` trap, the mixin shape, and the coverage
-  behaviour of new sibling modules. `python_pkg` is done; read it if a stray
-  `.py` turns up, or for the seam rule, which generalises to any language.
+- `docs/python-split-recipes.md` — the seam-selection rule (generalises to
+  every language), the `__all__` re-export form, the `TC001` trap and the
+  mixin shape. `python_pkg` is done.
+- `docs/app-split-recipes.md` — Dart `part`, Kotlin fixture objects, the
+  TypeScript import cycle that compiles clean, and the per-project test
+  baselines. **Read before touching `billsplit` or `focus_owner`.**
 - `docs/shell-split-recipes.md` — **read this before the next
   `linux_configuration` split.** What replaces the pass count when there is no
   test suite, which scripts escape the repo, the lib shape that satisfies both
@@ -154,23 +161,10 @@ Each rule in both cost a failed gate run or a revert to establish.
 - **Shell** — extract into `lib/*.sh` sourced by a thin entry script. See
   `docs/shell-split-recipes.md` for the lib shape; note it corrects the old
   advice to repeat `set -euo pipefail` in every lib.
-- **Python** — extract cohesive helpers into sibling modules; keep the public
-  API stable by re-exporting.
-- **TS/Dart** — extract components; re-export from the original path so no
-  importer changes.
-- **Tests** — split by describe/test-group. Coverage must not drop, and
-  **verify by the pass _count_, not a green run**: a split that loses a whole
-  module still reports "passed".
-  In `python_pkg`, shared fixture builders go in the package's
-  **`tests/conftest.py`** — the `name-tests-test` hook rejects any other
-  non-`test_*.py` file under `tests/`, so a `_helpers.py` will fail the gate.
-  `python_pkg/syncyomi_guard/tests/conftest.py` is the precedent, and
-  `meta/pyproject.toml` omits `*/tests/*` from coverage by path so nothing
-  there is counted as production code (the opposite of the `poker-stakes`
-  trap below). Prefer one shared conftest over another `partN` file: the repo
-  already carries four, and each new one that redeclares the same fixture
-  scaffolding pushes jscpd toward its 2% duplication threshold — which only
-  fires on the real `git commit`.
+- **Python / TS / Dart / Kotlin** — see the two recipe docs above.
+- **Tests** — split by describe/test-group and **verify by the pass _count_,
+  not a green run**: a split that loses a whole module still reports "passed".
+  Shared fixtures go where the coverage config already excludes them.
 
 Never game the cap: no one-lining, no deleting tests, no moving code into an
 exempt extension, no suppressions.