test(cli): relocate the _open example twins to tests/fixtures (refs #248)

The four _open blueprints leave the user-facing gallery
(crates/aura-cli/examples/) and become test fixtures; the closed twins
are now the only example corpus (bound params are overridable defaults
since #246, so the closed files serve both run and sweep).

Compile-time embeds follow the move: the emit_* generators and the
shipped_*_serialize byte-pins target tests/fixtures/ (the open fixtures
stay builder-generated and byte-pinned — regenerating after the move
left the tree clean), load_open_r_sma and the axis-probe read the
fixture, and the walk-forward refit test plus the `aura graph` default
sample switch to the closed r_sma.json. graph_construct's open-fixture
tests swap example() -> fixture(), their names dropping the now-false
"shipped example" claim; a new e2e test pins the relocation property
(all four fixtures load and introspect, the gallery holds exactly the
four closed examples).

Intermediate state: cli_run.rs / research_docs.rs / project_load.rs
still reference the old example paths and fail at runtime until the
follow-up migration commit (MIGRATE sites move to the closed twins,
NEEDS-OPEN sites to the fixtures).

Verification: cargo build --workspace; cargo test -p aura-cli --bin
aura; cargo test -p aura-cli --test graph_construct; the three ignored
emit generators re-run byte-stable.

crates/aura-cli/tests/graph_construct.rs

@@ -471,7 +471,7 @@ fn graph_register_is_idempotent() {
 fn graph_params_lists_raw_axis_namespace() {
     let dir = temp_cwd("params");
     let (stdout, stderr, code) =
-        run_in(&dir, &["graph", "introspect", "--params", &example("r_sma_open.json")]);
+        run_in(&dir, &["graph", "introspect", "--params", &fixture("r_sma_open.json")]);
     assert_eq!(code, Some(0), "stdout: {stdout} stderr: {stderr}");
     assert_eq!(stdout, "fast.length:I64\nslow.length:I64\n", "the raw open params, in order");
 }
@@ -512,7 +512,7 @@ fn graph_introspect_mode_guard_still_exits_two_on_zero_or_two_modes() {
 #[test]
 fn graph_params_by_content_id_matches_params_by_file() {
     let dir = temp_cwd("params-by-id");
-    let bp = example("r_sma_open.json");
+    let bp = fixture("r_sma_open.json");
     let (reg_out, reg_err, reg_code) = run_in(&dir, &["graph", "register", &bp]);
     assert_eq!(reg_code, Some(0), "register: {reg_out} {reg_err}");
     let id = registered_id(&reg_out);
@@ -533,7 +533,7 @@ fn graph_params_by_content_id_matches_params_by_file() {
 #[test]
 fn graph_params_tolerates_content_prefix_on_target() {
     let dir = temp_cwd("params-content-prefix");
-    let bp = example("r_sma_open.json");
+    let bp = fixture("r_sma_open.json");
     let (reg_out, reg_err, reg_code) = run_in(&dir, &["graph", "register", &bp]);
     assert_eq!(reg_code, Some(0), "register: {reg_out} {reg_err}");
     let id = registered_id(&reg_out);
@@ -744,7 +744,7 @@ fn shipped_r_sma_example_is_genuinely_closed() {
     assert_eq!(stdout, "", "the closed example must leave zero params unbound");
 }
 
-/// Property (#159): the shipped open example (`examples/r_sma_open.json`) is a
+/// Property (#159): the open fixture (`tests/fixtures/r_sma_open.json`) is a
 /// usable sweep-axis template from its public gallery location, not just a
 /// byte-identical artifact — `graph introspect --params` lists exactly the two
 /// unbound SMA lengths, in lowering order, matching the raw axis namespace the
@@ -753,10 +753,10 @@ fn shipped_r_sma_example_is_genuinely_closed() {
 /// shipped copy is actually introspectable/bindable from where a consumer runs
 /// it.
 #[test]
-fn shipped_r_sma_open_example_lists_its_axis_namespace() {
+fn open_r_sma_fixture_lists_its_axis_namespace() {
     let dir = temp_cwd("example-open-params");
     let (stdout, stderr, code) =
-        run_in(&dir, &["graph", "introspect", "--params", &example("r_sma_open.json")]);
+        run_in(&dir, &["graph", "introspect", "--params", &fixture("r_sma_open.json")]);
     assert_eq!(code, Some(0), "stdout: {stdout} stderr: {stderr}");
     assert_eq!(
         stdout, "fast.length:I64\nslow.length:I64\n",
@@ -764,6 +764,31 @@ fn shipped_r_sma_open_example_lists_its_axis_namespace() {
     );
 }
 
+/// Property (#248): the four `_open` blueprint twins were RELOCATED out of the
+/// public gallery, not deleted — each stem is present under `tests/fixtures/`
+/// (the internal sweep-axis fixture location) and absent from `examples/` (the
+/// public, user-facing gallery). This is the acceptance criterion's core claim
+/// ("`examples/` ships no `_open` variants") stated as a filesystem fact, so a
+/// future example addition that reintroduces a twin — or a migration that moves
+/// the reference but forgets the file — fails here even though every
+/// `include_str!`/path-string call site already resolves.
+#[test]
+fn open_twins_are_relocated_from_examples_to_fixtures_not_deleted() {
+    let manifest_dir = env!("CARGO_MANIFEST_DIR");
+    for stem in ["r_sma", "r_breakout", "r_meanrev", "r_channel"] {
+        let gallery_path = format!("{manifest_dir}/examples/{stem}_open.json");
+        assert!(
+            !std::path::Path::new(&gallery_path).exists(),
+            "{stem}_open.json must not ship in the public examples/ gallery (#248)"
+        );
+        let fixture_path = format!("{manifest_dir}/tests/fixtures/{stem}_open.json");
+        assert!(
+            std::path::Path::new(&fixture_path).exists(),
+            "{stem}_open.json must survive relocated under tests/fixtures/ (#248)"
+        );
+    }
+}
+
 /// Property (#159 cut 2): the shipped closed example (`examples/r_breakout.json`) is
 /// genuinely closed — `graph introspect --params` reports zero unbound params.
 #[test]
@@ -775,14 +800,14 @@ fn shipped_r_breakout_example_is_genuinely_closed() {
     assert_eq!(stdout, "", "the closed example must leave zero params unbound");
 }
 
-/// Property (#159 cut 2): the shipped open example (`examples/r_breakout_open.json`)
+/// Property (#159 cut 2): the open fixture (`tests/fixtures/r_breakout_open.json`)
 /// lists its ONE ganged channel axis (#61: the two rolling windows are structurally
 /// one knob).
 #[test]
-fn shipped_r_breakout_open_example_lists_its_axis_namespace() {
+fn open_r_breakout_fixture_lists_its_axis_namespace() {
     let dir = temp_cwd("r-breakout-example-open-params");
     let (stdout, stderr, code) =
-        run_in(&dir, &["graph", "introspect", "--params", &example("r_breakout_open.json")]);
+        run_in(&dir, &["graph", "introspect", "--params", &fixture("r_breakout_open.json")]);
     assert_eq!(code, Some(0), "stdout: {stdout} stderr: {stderr}");
     assert_eq!(
         stdout, "channel_length:I64\n",
@@ -805,7 +830,7 @@ fn shipped_r_breakout_open_example_lists_its_axis_namespace() {
 /// member) would be caught here even if the internal builder-level
 /// equivalence still holds.
 #[test]
-fn shipped_r_breakout_open_gang_axis_matches_the_closed_example() {
+fn open_r_breakout_fixture_gang_axis_matches_the_closed_example() {
     let closed_dir = temp_cwd("r-breakout-gang-axis-closed");
     let (closed_stdout, closed_stderr, closed_code) = run_in(&closed_dir, &["run", &example("r_breakout.json")]);
     assert_eq!(closed_code, Some(0), "closed run stderr: {closed_stderr}");
@@ -815,7 +840,7 @@ fn shipped_r_breakout_open_gang_axis_matches_the_closed_example() {
     let sweep_dir = temp_cwd("r-breakout-gang-axis-sweep");
     let (sweep_stdout, sweep_stderr, sweep_code) = run_in(
         &sweep_dir,
-        &["sweep", &example("r_breakout_open.json"), "--axis", "r_breakout_signal.channel_length=3"],
+        &["sweep", &fixture("r_breakout_open.json"), "--axis", "r_breakout_signal.channel_length=3"],
     );
     assert_eq!(sweep_code, Some(0), "sweep stderr: {sweep_stderr}");
     let lines: Vec<&str> = sweep_stdout.lines().collect();
@@ -840,13 +865,13 @@ fn shipped_r_meanrev_example_is_genuinely_closed() {
     assert_eq!(stdout, "", "the closed example must leave zero params unbound");
 }
 
-/// Property (#159 cut 3): the shipped open example (`examples/r_meanrev_open.json`)
+/// Property (#159 cut 3): the open fixture (`tests/fixtures/r_meanrev_open.json`)
 /// lists its raw axis namespace, in lowering (node-add) order.
 #[test]
-fn shipped_r_meanrev_open_example_lists_its_axis_namespace() {
+fn open_r_meanrev_fixture_lists_its_axis_namespace() {
     let dir = temp_cwd("r-meanrev-example-open-params");
     let (stdout, stderr, code) =
-        run_in(&dir, &["graph", "introspect", "--params", &example("r_meanrev_open.json")]);
+        run_in(&dir, &["graph", "introspect", "--params", &fixture("r_meanrev_open.json")]);
     assert_eq!(code, Some(0), "stdout: {stdout} stderr: {stderr}");
     assert_eq!(
         stdout, "window:I64\nband.factor:F64\n",
@@ -863,7 +888,7 @@ fn shipped_r_meanrev_open_example_lists_its_axis_namespace() {
 /// param positions could silently mis-bind the co-present un-ganged axis
 /// instead (or vice-versa) even though each axis alone still resolves.
 #[test]
-fn shipped_r_meanrev_open_gang_plus_plain_axis_matches_the_closed_example() {
+fn open_r_meanrev_fixture_gang_plus_plain_axis_matches_the_closed_example() {
     let closed_dir = temp_cwd("r-meanrev-gang-axis-closed");
     let (closed_stdout, closed_stderr, closed_code) = run_in(&closed_dir, &["run", &example("r_meanrev.json")]);
     assert_eq!(closed_code, Some(0), "closed run stderr: {closed_stderr}");
@@ -874,7 +899,7 @@ fn shipped_r_meanrev_open_gang_plus_plain_axis_matches_the_closed_example() {
     let (sweep_stdout, sweep_stderr, sweep_code) = run_in(
         &sweep_dir,
         &[
-            "sweep", &example("r_meanrev_open.json"),
+            "sweep", &fixture("r_meanrev_open.json"),
             "--axis", "r_meanrev_signal.window=3",
             "--axis", "r_meanrev_signal.band.factor=2.0",
         ],