Add frontend editor support for PickValueModule

Palette entry, icon mappings, FormPickValue component with mode
selector and grow-on-connect, type union updates across stores.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/src/components/Workflow/Editor/Forms/FormDefault.vue

@@ -43,8 +43,12 @@
                 v-if="isSubworkflow"
                 :step="step"
                 @onUpdateStep="(id, step) => emit('onUpdateStep', id, step)" />
+            <FormPickValue
+                v-if="type == 'pick_value'"
+                :step="step"
+                @onChange="onChange" />
             <FormInputCollection
-                v-if="type == 'data_collection_input'"
+                v-else-if="type == 'data_collection_input'"
                 :step="step"
                 :datatypes="datatypes"
                 :inputs="configForm?.inputs"
@@ -87,6 +91,7 @@ import FormDisplay from "@/components/Form/FormDisplay.vue";
 import FormElement from "@/components/Form/FormElement.vue";
 import FormInputCollection from "@/components/Workflow/Editor/Forms/FormInputCollection.vue";
 import FormOutputLabel from "@/components/Workflow/Editor/Forms/FormOutputLabel.vue";
+import FormPickValue from "@/components/Workflow/Editor/Forms/FormPickValue.vue";
 
 const props = defineProps<{
     step: Step;

client/src/components/Workflow/Editor/Forms/FormPickValue.vue

@@ -0,0 +1,81 @@
+<script setup lang="ts">
+import { toRef, watch } from "vue";
+
+import type { Step } from "@/stores/workflowStepStore";
+
+import { useToolState } from "../composables/useToolState";
+
+import FormElement from "@/components/Form/FormElement.vue";
+
+interface ToolState {
+    mode: string;
+    num_inputs: number;
+}
+
+const props = defineProps<{
+    step: Step;
+}>();
+
+const stepRef = toRef(props, "step");
+const { toolState } = useToolState(stepRef);
+
+function asToolState(ts: unknown): ToolState {
+    const raw = ts as Record<string, unknown>;
+    return {
+        mode: (raw.mode as string) ?? "first_non_null",
+        num_inputs: (raw.num_inputs as number) ?? 2,
+    };
+}
+
+function cleanToolState(): ToolState {
+    if (toolState.value) {
+        return asToolState({ ...toolState.value });
+    }
+    return { mode: "first_non_null", num_inputs: 2 };
+}
+
+const emit = defineEmits(["onChange"]);
+
+const modeOptions = [
+    { value: "first_non_null", label: "First non-null (error if all null)" },
+    { value: "first_or_skip", label: "First non-null (skip if all null)" },
+    { value: "the_only_non_null", label: "The only non-null (error if != 1)" },
+    { value: "all_non_null", label: "All non-null (as collection)" },
+];
+
+function onMode(newMode: string) {
+    const state = cleanToolState();
+    state.mode = newMode;
+    emit("onChange", state);
+}
+
+// Grow-on-connect: watch step connections, add terminal when last empty one gets connected
+watch(
+    () => props.step.input_connections,
+    (connections) => {
+        const state = cleanToolState();
+        const lastTerminalName = `input_${state.num_inputs}`;
+        if (connections && connections[lastTerminalName]) {
+            state.num_inputs = state.num_inputs + 1;
+            emit("onChange", state);
+        }
+    },
+    { deep: true }
+);
+
+// Dummy initial emit (same pattern as FormInputCollection — resets initialChange guard)
+emit("onChange", cleanToolState());
+</script>
+
+<template>
+    <div>
+        <FormElement
+            id="mode"
+            :value="asToolState(toolState).mode"
+            title="Selection Mode"
+            type="select"
+            :options="modeOptions"
+            help="How to select among the connected inputs."
+            @input="onMode" />
+    </div>
+</template>

client/src/components/Workflow/Editor/modules/inputs.ts

@@ -1,5 +1,5 @@
 import { faFile, faFolder } from "@fortawesome/free-regular-svg-icons";
-import { faPencilAlt } from "@fortawesome/free-solid-svg-icons";
+import { faCodeBranch, faPencilAlt } from "@fortawesome/free-solid-svg-icons";
 import type { IconDefinition } from "font-awesome-6";
 
 export interface WorkflowInput {
@@ -96,5 +96,11 @@ export function getWorkflowInputs(): WorkflowInput[] {
                 parameter_type: "directory_uri",
             },
         },
+        {
+            moduleId: "pick_value",
+            title: "Pick Value",
+            description: "Select among conditional branch outputs",
+            icon: faCodeBranch,
+        },
     ];
 }

client/src/components/Workflow/Editor/modules/itemIcons.ts

@@ -1,6 +1,7 @@
 import {
     faArrowRightFromBracket,
     faArrowRightToBracket,
+    faCodeBranch,
     faComment,
     faFile,
     faFolderOpen,
@@ -22,6 +23,7 @@ export const iconForType = {
         parameter_input: faPen,
         subworkflow: faSitemap,
         pause: faPause,
+        pick_value: faCodeBranch,
     },
     input: faArrowRightToBracket,
     output: faArrowRightFromBracket,

client/src/components/Workflow/icons.js

@@ -5,4 +5,5 @@ export default {
     subworkflow: "fa-sitemap fa-rotate-270",
     parameter_input: "fa-pencil-alt", // fa-pencil for older FontAwesome, fa-pencil-alt for newer
     pause: "fa-pause",
+    pick_value: "fa-code-branch",
 };

client/src/components/WorkflowInvocationState/WorkflowStepIcon.vue

@@ -5,7 +5,7 @@ import { computed } from "vue";
 import WorkflowIcons from "@/components/Workflow/icons";
 
 interface WorkflowStepIconProps {
-    stepType: "tool" | "data_input" | "data_collection_input" | "subworkflow" | "parameter_input" | "pause";
+    stepType: "tool" | "data_input" | "data_collection_input" | "subworkflow" | "parameter_input" | "pause" | "pick_value";
 }
 
 const props = defineProps<WorkflowStepIconProps>();

client/src/stores/workflowNodeInspectorStore.ts

@@ -21,6 +21,7 @@ function getContentId(step: Step) {
         data_input: () => "input",
         parameter_input: () => "input",
         pause: () => "pause",
+        pick_value: () => "pick_value",
     });
 }
 

client/src/stores/workflowStepStore.ts

@@ -113,7 +113,7 @@ export interface NewStep {
     tool_state: Record<string, unknown>;
     tool_version?: string;
     tooltip?: string | null;
-    type: "tool" | "data_input" | "data_collection_input" | "subworkflow" | "parameter_input" | "pause";
+    type: "tool" | "data_input" | "data_collection_input" | "subworkflow" | "parameter_input" | "pause" | "pick_value";
     uuid?: string;
     when?: string | null;
     workflow_id?: string;