fix(canvas): WCAG SC 1.3.1 — programmatic label/input association in InputField

Adds useId() to the InputField helper in CreateWorkspaceDialog so every
<label> is wired to its <input> via htmlFor/id. Without this, screen readers
announced only the placeholder text, not the field name (WCAG 2.1 SC 1.3.1
Level A violation, build 4JIwTGVMjDGNLO8iMGJeC).

Affected fields: Name (required), Role, Budget limit (USD), Template.
The Hermes provider fields were already correctly wired.

Adds 6 new tests in CreateWorkspaceDialog.a11y.test.tsx verifying htmlFor/id
round-trips for each field and unique-id non-collision (602 total, all pass;
build clean; 'use client' grep empty).

Note: #554 (hydration error UI) and #556 (tier radio arrow-key nav) are
confirmed fixed in commit 76defba — audit cycle 2 was run against the
pre-fix build. #557 (zoom-to-team Z key) is a false positive — the handler
IS implemented; closing via Dev Lead once token is refreshed.

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

canvas/src/components/CreateWorkspaceDialog.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useState, useEffect, useRef, useCallback } from "react";
+import { useState, useEffect, useRef, useCallback, useId } from "react";
 import * as Dialog from "@radix-ui/react-dialog";
 import { api } from "@/lib/api";
 
@@ -368,9 +368,13 @@ function InputField({
   type?: string;
   helper?: string;
 }) {
+  // useId() generates a stable, unique ID for the label↔input association,
+  // satisfying WCAG 2.1 SC 1.3.1 (Info and Relationships, Level A).
+  const inputId = useId();
+
   return (
     <div>
-      <label className="text-[11px] text-zinc-400 block mb-1">
+      <label htmlFor={inputId} className="text-[11px] text-zinc-400 block mb-1">
         {label}{" "}
         {required && (
           <>
@@ -382,6 +386,7 @@ function InputField({
         )}
       </label>
       <input
+        id={inputId}
         type={type}
         value={value}
         onChange={(e) => onChange(e.target.value)}

canvas/src/components/__tests__/CreateWorkspaceDialog.a11y.test.tsx

@@ -161,3 +161,72 @@ describe("CreateWorkspaceDialog — accessibility", () => {
     await waitFor(() => expect(t3.getAttribute("aria-checked")).toBe("true"));
   });
 });
+
+// ── WCAG 2.1 SC 1.3.1 — Programmatic label association (Issue #558) ──────────
+//
+// Every <input> rendered by the InputField helper must have a matching <label>
+// via htmlFor/id so screen readers announce the field name, not just the
+// placeholder.  useId() in InputField generates stable unique IDs per render.
+
+describe("CreateWorkspaceDialog — WCAG SC 1.3.1 label/input association", () => {
+  it("Name input has a <label> whose htmlFor matches the input id", async () => {
+    await openDialog();
+    const nameInput = screen.getByPlaceholderText("e.g. SEO Agent") as HTMLInputElement;
+    expect(nameInput.id).toBeTruthy();
+    const label = document.querySelector(`label[for="${nameInput.id}"]`);
+    expect(label).toBeTruthy();
+    expect(label?.textContent).toContain("Name");
+  });
+
+  it("Role input has a <label> whose htmlFor matches the input id", async () => {
+    await openDialog();
+    const roleInput = screen.getByPlaceholderText("e.g. SEO Specialist") as HTMLInputElement;
+    expect(roleInput.id).toBeTruthy();
+    const label = document.querySelector(`label[for="${roleInput.id}"]`);
+    expect(label).toBeTruthy();
+    expect(label?.textContent).toContain("Role");
+  });
+
+  it("Budget limit input has a <label> whose htmlFor matches the input id", async () => {
+    await openDialog();
+    const budgetInput = screen.getByPlaceholderText("e.g. 100") as HTMLInputElement;
+    expect(budgetInput.id).toBeTruthy();
+    const label = document.querySelector(`label[for="${budgetInput.id}"]`);
+    expect(label).toBeTruthy();
+    expect(label?.textContent).toContain("Budget limit");
+  });
+
+  it("Template input has a <label> whose htmlFor matches the input id", async () => {
+    await openDialog();
+    const templateInput = screen.getByPlaceholderText(
+      "e.g. seo-agent (from workspace-configs-templates/)"
+    ) as HTMLInputElement;
+    expect(templateInput.id).toBeTruthy();
+    const label = document.querySelector(`label[for="${templateInput.id}"]`);
+    expect(label).toBeTruthy();
+    expect(label?.textContent).toContain("Template");
+  });
+
+  it("each InputField generates a distinct id (no id collisions)", async () => {
+    await openDialog();
+    const inputs = [
+      screen.getByPlaceholderText("e.g. SEO Agent"),
+      screen.getByPlaceholderText("e.g. SEO Specialist"),
+      screen.getByPlaceholderText("e.g. 100"),
+      screen.getByPlaceholderText("e.g. seo-agent (from workspace-configs-templates/)"),
+    ] as HTMLInputElement[];
+
+    const ids = inputs.map((i) => i.id).filter(Boolean);
+    const unique = new Set(ids);
+    expect(unique.size).toBe(ids.length); // no duplicates
+    expect(ids.length).toBe(4);
+  });
+
+  it("Name label text contains the required asterisk indicator", async () => {
+    await openDialog();
+    const nameInput = screen.getByPlaceholderText("e.g. SEO Agent") as HTMLInputElement;
+    const label = document.querySelector(`label[for="${nameInput.id}"]`);
+    // aria-hidden asterisk * is present for visual required indicator
+    expect(label?.querySelector("[aria-hidden='true']")?.textContent).toBe("*");
+  });
+});