FN-7301: add icon workflow picker to new task form

Add an icon-capable New Task workflow picker that preserves create-time workflow selection semantics.

- Replace the native workflow select in TaskForm with a styled dropdown showing workflow icons, default badges, duplicate-name IDs, and explicit No workflow opt-out.
- Wire the inline workflow chip to reveal and open the new picker while keeping workflowId payload handling unchanged.
- Add dropdown layout styles, dashboard docs, release notes, and regression coverage for modal create flows and TaskForm selection behavior.

Files changed:
 .changeset/fn-7301-new-task-workflow-dropdown.md   |   7 +
 docs/dashboard-guide.md                            |   3 +
 packages/dashboard/app/components/NewTaskModal.css |  75 ++++++++++
 packages/dashboard/app/components/TaskForm.tsx     | 166 ++++++++++++++++-----
 .../app/components/__tests__/NewTaskModal.test.tsx |  61 ++++++--
 .../app/components/__tests__/TaskForm.test.tsx     | 128 +++++++++++-----
 6 files changed, 351 insertions(+), 89 deletions(-)

Fusion-Task-Id: FN-7301

Fusion-Task-Lineage: f3d534a2-48bd-416a-88a6-f85410ee4f85

Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>

docs/dashboard-guide.md

@@ -232,6 +232,9 @@ Behavior:
 
 Workflows define how a task moves through planning, execution, review, workflow steps, merge, and any custom graph policy. Most coding tasks can stay on the default Coding workflow, but task and board workflow controls can select a different built-in or custom workflow per task. For the built-in catalog and runtime semantics, see [Workflow Steps → Workflow overview](./workflow-steps.md#workflow-overview).
 
+<!-- FNXC:NewTaskWorkflowDropdown 2026-06-30-18:52: The full New Task dialog workflow picker now matches the icon-rich workflow identity used in Board/List selectors while preserving create-time workflowId semantics. -->
+When creating a task from the full **New Task** dialog, the **Workflow** advanced control opens a styled dropdown instead of a native select. Built-in workflows show the Fusion mark, custom workflows show their configured compact icon when present, **No workflow** remains the explicit opt-out, and leaving the picker untouched still inherits the project/default workflow.
+
 The workflow editor opens as a full-screen modal editor for inspecting built-ins and authoring custom workflows.
 
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