fix(FN-7591): allow moving tasks out of custom workflow columns (Coding (Ideas))

Moving a card out of a non-legacy workflow column — e.g. Coding (Ideas)
"ideas" → "todo" — was rejected with "Invalid transition: 'ideas' → 'todo'.
Valid targets: none".

Workflow columns graduated to always-on but moveTaskInternal's compat-flag
legacy branch (the default path, since no experimental flag is emitted)
validated every move against the legacy VALID_TRANSITIONS table, which is
keyed only by the built-in column ids. Default-workflow moves survived by
coincidence (its ids ARE the legacy ids); a task in a custom column had no
key so every move was rejected.

The legacy branch now resolves a non-legacy source column's targets from the
task's own workflow adjacency (resolveAllowedColumns), while keeping the
legacy bare-Error contract intact for legacy columns (transition-parity /
characterization suites unchanged). Adds a regression test covering the
ideas -> todo -> in-progress -> in-review chain and non-adjacent rejection.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.changeset/coding-ideas-custom-column-move.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Fix "Invalid transition" error when moving cards out of a custom workflow column like Coding (Ideas) → Ideas.
+category: fix
+dev: moveTaskInternal's compat-flag legacy path validated moves against the legacy VALID_TRANSITIONS table, which is keyed only by the built-in column ids; a task in a non-legacy workflow column (e.g. "ideas") had no key and every move was rejected. The legacy branch now resolves a non-legacy source column's targets from the task's own workflow adjacency (resolveAllowedColumns) while preserving the legacy bare-Error contract for legacy columns.

packages/core/src/__tests__/coding-ideas-move.test.ts

@@ -0,0 +1,59 @@
+import { describe, it, expect, beforeEach, afterEach } from "vitest";
+import { createTaskStoreTestHarness } from "./store-test-helpers.js";
+
+/*
+FNXC:WorkflowColumns 2026-07-05-19:10:
+Regression for the disappearing move on custom workflow columns. Workflow columns graduated to
+always-on (no experimental flag emitted), but moveTaskInternal still gated its workflow path on the
+retired strict compatibility flag, so it fell back to the legacy VALID_TRANSITIONS table — which is
+keyed only by the legacy column ids. A task in a non-legacy column (Coding (Ideas) → "ideas") could
+not move: "Invalid transition: 'ideas' → 'todo'. Valid targets: none".
+
+Surface enumeration (invariant: a move is validated by the task's WORKFLOW adjacency, not the legacy
+table, on a default project with NO experimental flag set):
+ - Custom intake column forward move: ideas → todo is allowed.
+ - Full custom-column chain onward: todo → in-progress → in-review all succeed (→ done is gated by the
+   workflow's own merge trait, which is orthogonal to transition adjacency and excluded here).
+ - Non-adjacent move still rejects with the workflow's targets (ideas → in-progress).
+ - Holds for both user- and engine-sourced moves.
+ - Default workflow (legacy column ids) is unchanged (parity), verified in move-task-characterization.
+*/
+describe("Coding (Ideas) custom-column moves (workflow-columns graduation)", () => {
+  const harness = createTaskStoreTestHarness();
+  beforeEach(harness.beforeEach);
+  afterEach(harness.afterEach);
+
+  it("moves an ideas-workflow task from the ideas intake column to todo", async () => {
+    const store = harness.store();
+    const task = await store.createTask({ description: "idea", workflowId: "builtin:coding-ideas" });
+    expect(task.column).toBe("ideas");
+
+    const moved = await store.moveTask(task.id, "todo", { moveSource: "user" });
+    expect(moved.column).toBe("todo");
+  });
+
+  it("advances an ideas task along the Coding (Ideas) custom-column chain", async () => {
+    const store = harness.store();
+    const task = await store.createTask({ description: "idea", workflowId: "builtin:coding-ideas" });
+
+    await store.moveTask(task.id, "todo", { moveSource: "user" });
+    await store.moveTask(task.id, "in-progress", { moveSource: "user" });
+    const inReview = await store.moveTask(task.id, "in-review", { moveSource: "user", allowDirectInReviewMove: true });
+    expect(inReview.column).toBe("in-review");
+  });
+
+  it("still rejects a non-adjacent move out of the ideas column", async () => {
+    const store = harness.store();
+    const task = await store.createTask({ description: "idea", workflowId: "builtin:coding-ideas" });
+    await expect(
+      store.moveTask(task.id, "in-progress", { moveSource: "user" }),
+    ).rejects.toThrow(/Invalid transition: 'ideas' → 'in-progress'/);
+  });
+
+  it("allows the ideas → todo move from an engine source too", async () => {
+    const store = harness.store();
+    const task = await store.createTask({ description: "idea", workflowId: "builtin:coding-ideas" });
+    const moved = await store.moveTask(task.id, "todo", { moveSource: "engine" });
+    expect(moved.column).toBe("todo");
+  });
+});

packages/core/src/store.ts

@@ -7676,11 +7676,22 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
         !sourceIsLegacy &&
         (COLUMNS as readonly string[]).includes(toColumn);
       if (!isEvacuation) {
-        // Legacy flag-OFF branch (useWorkflow === false): both columns are
-        // guaranteed legacy ids here — a non-legacy `toColumn` returns `?? []`
-        // and rejects below, and flag-OFF tasks never hold custom column ids.
-        // The `as Column` is provably safe within this branch (#1403).
-        const validTargets = VALID_TRANSITIONS[task.column as Column] ?? [];
+        /*
+        FNXC:WorkflowColumns 2026-07-05-19:30:
+        Workflow columns graduated to always-on (no experimental flag emitted), so this "flag-OFF"
+        branch is the DEFAULT move path for nearly every project — the strict compat flag reads false
+        because nothing sets it. Legacy columns (triage/todo/in-progress/in-review/done/archived) are
+        validated verbatim by VALID_TRANSITIONS, preserving the legacy bare-Error contract. But a task
+        can legitimately sit in a NON-legacy workflow column now (e.g. Coding (Ideas) → "ideas"), which
+        VALID_TRANSITIONS cannot key — the old code returned `?? []` and rejected EVERY move out of it
+        ("Invalid transition: 'ideas' → 'todo'. Valid targets: none"). Resolve a non-legacy source
+        column's targets from the task's own workflow adjacency instead, still throwing the same
+        legacy-style bare Error (not TransitionRejectionError) so the flag-OFF characterization contract
+        holds for legacy columns.
+        */
+        const validTargets = sourceIsLegacy
+          ? (VALID_TRANSITIONS[task.column as Column] ?? [])
+          : resolveAllowedColumns(this.resolveTaskWorkflowIrSync(id), task.column);
         if (!validTargets.includes(toColumn as Column)) {
           throw new Error(
             `Invalid transition: '${task.column}' → '${toColumn}'. ` +