feat(publish): S6 Woo create sequence + UAT draft + dup/stale/partial failure + Publish UI

- backend/publish.py: POST /slabs/{id}/publish. Sequence (PUBLISH-5): validate ready
  set -> SKU lookup (409 on dup, PUBLISH-15) -> refresh taxonomy if >1h (SETTINGS-60)
  -> resolve cats/tags/5 attributes -> upload processed PNGs -> POST /products ->
  finalize (set woo_product_id, purge photos, PUBLISH-25). SLAB-UAT-* always draft
  (PUBLISH-10). Failure: mark failed, retain photos, sync_log, plain recoverable/
  unrecoverable message (PUBLISH-30/36/37/38). Partial (media ok, POST failed):
  orphan media logged + manual cleanup note (PUBLISH-31). Payload: only non-null,
  slug = name+sku, sold_individually true (PUBLISH-55/60).
- frontend: create/publish/Publish.svelte (slab id, publish, result + recoverable/
  orphan tags) + dev toggle.
- tests: 5 publish tests (success+purge, UAT draft, not-ready 422, dup 409,
  partial-media 502). Woo transport mocked.

Verified: pytest 48 passed; gates exit 0; npm build ok.

frontend/src/App.svelte

@@ -13,6 +13,7 @@ import Settings from './create/settings/Settings.svelte';
 import SlabList from './create/slabs/SlabList.svelte';
 import PhotoAttach from './create/photos/PhotoAttach.svelte';
 import Review from './create/review/Review.svelte';
+import Publish from './create/publish/Publish.svelte';
 
   const gate = typeof window !== 'undefined' ? supported() : 'window unavailable';
   const session: CaptureSession = createCaptureSession();
@@ -24,6 +25,7 @@ import Review from './create/review/Review.svelte';
   let showSlabs = false;
   let showPhotos = false;
   let showReview = false;
+  let showPublish = false;
 
   const unsubCap = session.capture.subscribe((c) => {
     cap = c;
@@ -101,6 +103,7 @@ import Review from './create/review/Review.svelte';
       <button on:click={() => (showSlabs = !showSlabs)}>Slabs (dev)</button>
       <button on:click={() => (showPhotos = !showPhotos)}>Photos (dev)</button>
       <button on:click={() => (showReview = !showReview)}>Review (dev)</button>
+      <button on:click={() => (showPublish = !showPublish)}>Publish (dev)</button>
     </div>
     {#if showSettings}
       <Settings />
@@ -114,6 +117,9 @@ import Review from './create/review/Review.svelte';
     {#if showReview}
       <Review />
     {/if}
+    {#if showPublish}
+      <Publish />
+    {/if}
   </main>
 {/if}
 

frontend/src/create/publish/Publish.svelte

@@ -0,0 +1,69 @@
+<script lang="ts">
+  let slabId = '';
+  let result: {
+    ok?: boolean;
+    status?: string;
+    woo_product_id?: number;
+    draft?: boolean;
+    error?: { code: string; message: string; detail?: Record<string, unknown> };
+  } | null = null;
+  let busy = false;
+
+  async function publish() {
+    if (!slabId) {
+      result = { error: { code: 'input', message: 'Enter a slab id.' } };
+      return;
+    }
+    busy = true;
+    result = null;
+    try {
+      const res = await fetch(`/api/v1/slabs/${encodeURIComponent(slabId)}/publish`, { method: 'POST' });
+      const body = await res.json();
+      if (res.ok) result = body;
+      else result = { ok: false, error: body.error };
+    } catch {
+      result = { ok: false, error: { code: 'network', message: 'network error' } };
+    }
+    busy = false;
+  }
+</script>
+
+<div class="publish">
+  <h2>Publish to WooCommerce</h2>
+  <div>
+    <label>Slab ID</label>
+    <input bind:value={slabId} placeholder="uuid" />
+  </div>
+  <button on:click={publish} disabled={busy}>{busy ? 'Publishing…' : 'Publish'}</button>
+
+  {#if result}
+    {#if result.ok}
+      <p class="ok">
+        Published{result.draft ? ' (UAT draft)' : ''} → Woo product #{result.woo_product_id}
+      </p>
+    {:else}
+      <p class="err">
+        {result.error?.message}
+        {#if result.error?.detail?.recoverable === false}
+          <span class="tag">unrecoverable</span>
+        {:else if result.error?.detail?.recoverable === true}
+          <span class="tag">recoverable — retry</span>
+        {/if}
+        {#if result.error?.detail?.partial_media}
+          <span class="tag warn">orphan media — clean up manually</span>
+        {/if}
+      </p>
+    {/if}
+  {/if}
+</div>
+
+<style>
+  .publish { max-width: 520px; color: #eee; }
+  label { display: block; margin: 8px 0 4px; }
+  input { width: 100%; padding: 6px; }
+  button { margin-top: 12px; }
+  .ok { margin-top: 12px; color: #7fd37f; font-weight: 600; }
+  .err { margin-top: 12px; color: #e88; }
+  .tag { margin-left: 8px; font-size: 12px; padding: 1px 6px; border-radius: 4px; background: #444; }
+  .tag.warn { background: #6a4; color: #000; }
+</style>