test(v4-6): all 6 schedule kinds through UI→train with shape assertions

Closes V4-6 / cppmega-mlx-08b. V3-5 only proved linear_warmup; v4-6
covers the full set: constant, linear_warmup, cosine, wsd, inv_sqrt,
polynomial.

Each scenario sets required ScheduleEditor fields per kind (warmup /
total / decay / power), Apply, Train N=8, asserts:
  - extras.schedule_kind matches selection
  - extras.model_summary.schedule_kind matches
  - lr_trajectory.length === 8
  - Shape per kind:
      constant: all equal
      linear_warmup w=4: lr[0]=0, lr[4]>lr[0]
      cosine total=8: monotone decay after warmup
      wsd: warmup → stable → decay
      inv_sqrt: ramp then 1/√t decay
      polynomial: (1-t/T)^power decay

6/6 green in 7.6s.

Author: apstenku123

vbgui/e2e/scenarios/20_schedule_propagation.spec.ts

@@ -0,0 +1,126 @@
+// V4-6: All 6 schedule kinds reach stage_train and shape lr_trajectory
+// correctly. V3-5 proved only linear_warmup; v4-6 covers the remaining
+// 5 + verifies analytical trajectory shape per kind.
+
+import { test, expect } from "@playwright/test";
+import { gotoApp, selectPreset, closeModal } from "../fixtures";
+import { readTrainExtras } from "../utils/train_extras";
+
+type Setup = {
+  warmup?: string;        // for non-constant schedules
+  total?: string;         // cosine / wsd / polynomial
+  decay?: string;         // wsd only
+  power?: string;         // polynomial only
+};
+
+interface Scenario {
+  kind: string;
+  setup: Setup;
+  /** Asserts lr_trajectory shape for N=8 steps with base_lr governed
+   *  by spec default group 0 lr (3e-4 for AdamW). */
+  assertTrajectory: (lr: number[]) => void;
+}
+
+const SCENARIOS: Scenario[] = [
+  {
+    kind: "constant",
+    setup: {},
+    assertTrajectory: (lr) => {
+      // All values equal (within rounding to 6 dp).
+      const first = lr[0];
+      for (const v of lr) expect(v).toBeCloseTo(first, 6);
+    },
+  },
+  {
+    kind: "linear_warmup",
+    setup: { warmup: "4" },
+    assertTrajectory: (lr) => {
+      // First step is ramp from 0; step 4+ is at base_lr.
+      expect(lr[0]).toBeCloseTo(0, 6);
+      expect(lr[4]).toBeGreaterThan(lr[0] + 1e-7);
+      expect(lr[4]).toBeGreaterThanOrEqual(lr[3]);
+    },
+  },
+  {
+    kind: "cosine",
+    setup: { warmup: "2", total: "8" },
+    assertTrajectory: (lr) => {
+      // After warmup, lr monotonically decays toward min_lr_ratio*base.
+      expect(lr[0]).toBeCloseTo(0, 6);
+      expect(lr[7]).toBeLessThan(lr[2]);
+    },
+  },
+  {
+    kind: "wsd",
+    setup: { warmup: "2", total: "8", decay: "4" },
+    assertTrajectory: (lr) => {
+      // Warmup → stable → decay. Last < peak.
+      expect(lr[0]).toBeCloseTo(0, 6);
+      expect(lr[7]).toBeLessThan(Math.max(...lr));
+    },
+  },
+  {
+    kind: "inv_sqrt",
+    setup: { warmup: "2" },
+    assertTrajectory: (lr) => {
+      // Warmup ramps then 1/sqrt decay.
+      expect(lr[0]).toBeCloseTo(0, 6);
+      expect(lr[7]).toBeLessThan(lr[2] + 1e-9);
+    },
+  },
+  {
+    kind: "polynomial",
+    setup: { warmup: "2", total: "8", power: "2" },
+    assertTrajectory: (lr) => {
+      // (1 - t/T)^power monotonic decay after warmup.
+      expect(lr[0]).toBeCloseTo(0, 6);
+      expect(lr[7]).toBeLessThan(lr[2]);
+    },
+  },
+];
+
+for (const { kind, setup, assertTrajectory } of SCENARIOS) {
+  test(`V4-6: schedule '${kind}' propagates kind + lr_trajectory shape`,
+    async ({ page }) => {
+      test.setTimeout(60_000);
+      await gotoApp(page);
+      await selectPreset(page, "llama3_8b");
+
+      await page.getByTestId("sidebar-tab-optim").click();
+      await page.getByTestId("optim-group-0-schedule-toggle").click();
+      await page.getByTestId("schedule-kind-0").selectOption(kind);
+      if (setup.warmup) {
+        await page.getByTestId("schedule-warmup-0").fill(setup.warmup);
+      }
+      if (setup.total) {
+        await page.getByTestId("schedule-total-0").fill(setup.total);
+      }
+      if (setup.decay) {
+        await page.getByTestId("schedule-decay-0").fill(setup.decay);
+      }
+      if (setup.power) {
+        await page.getByTestId("schedule-power-0").fill(setup.power);
+      }
+      await page.getByTestId("optim-apply").click();
+
+      // Run Train with N=8 so trajectory shape is observable.
+      await page.getByTestId("run-pipeline-toggle").click();
+      await page.getByTestId("train-num-steps").fill("8");
+      await page.getByTestId("run-pipeline-train").click();
+      const modal = page.getByTestId("run-result-modal");
+      await modal.waitFor({ timeout: 60_000 });
+
+      const extras = await readTrainExtras(page);
+
+      // Propagation
+      expect(extras.schedule_kind).toBe(kind);
+      expect(extras.model_summary.schedule_kind).toBe(kind);
+      expect(extras.num_steps).toBe(8);
+      expect(extras.lr_trajectory.length).toBe(8);
+
+      // Shape
+      assertTrajectory(extras.lr_trajectory);
+
+      await closeModal(page);
+    });
+}