fix(post): cover the code-review fixes; mark location-override plan complete

Adds Playwright coverage for the four cross-reviewer-confirmed bugs
fixed in the user/ submodule (map-load race on rapid reopen, mismatch
flag clearing on blank, and submit blocked on unresolved mismatch),
and bumps the user/ pointer to the commit with those fixes.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/working/plans/2026-07-23-post-form-location-override.md

@@ -11,7 +11,7 @@ execution: code
 
 # Post Form Location Override - Plan
 
-**Status:** 📋 Not started
+**Status:** ✅ Complete (2026-07-24)
 
 ## Goal Capsule
 

tests/ui/post/location-override.spec.js

@@ -258,6 +258,65 @@ test('typing an invalid lat value shows the mismatch flag and clears once fixed'
     await expect(page.locator('#location-map .maplibregl-marker')).toHaveCount(1);
 });
 
+// ── U4: rapid close/reopen while the maplibre-gl chunk is still in flight must
+// not build two Map instances against the same container (code-review fix) ──
+test('rapid close/reopen before the maplibre-gl chunk resolves still leaves exactly one canvas', async ({ page }) => {
+    await page.route('**/*maplibre-gl*.js', async (route) => {
+        await new Promise((resolve) => setTimeout(resolve, 500));
+        await route.continue();
+    });
+    await page.goto('/post');
+
+    // Open, then immediately close and reopen — both toggles land while the
+    // delayed chunk request above is still pending.
+    await page.locator('.location-details__summary').click();
+    await page.locator('.location-details__summary').click();
+    await page.locator('.location-details__summary').click();
+    await expect(page.locator('.location-details')).toHaveJSProperty('open', true);
+
+    await expect(page.locator('#location-map canvas.maplibregl-canvas')).toHaveCount(1, { timeout: 10_000 });
+});
+
+// ── U5: blanking both fields after a mismatch was flagged clears the flag ──
+test('blanking both lat/lng fields after a mismatch clears the flag', async ({ page }) => {
+    await page.goto('/post');
+    await openLocationDetails(page);
+
+    const latEl = page.locator('input[name="data[lat]"]');
+    const lngEl = page.locator('input[name="data[lng]"]');
+    await latEl.fill('not-a-number');
+    await lngEl.blur();
+    await expect(latEl).toHaveClass(/location-field--mismatch/);
+
+    await latEl.fill('');
+    await lngEl.fill('');
+    await lngEl.blur();
+    await expect(latEl).not.toHaveClass(/location-field--mismatch/);
+    await expect(lngEl).not.toHaveClass(/location-field--mismatch/);
+});
+
+// ── U5: a flagged, unresolved lat/lng must block submit (code-review fix) ──
+test('submitting with an unresolved lat/lng mismatch is blocked', async ({ page }) => {
+    const tag = `loc-mismatch-${Date.now()}`;
+    await page.goto('/post');
+    await page.fill('input[name="data[title]"]', `UI Test ${tag}`);
+    await fillEditor(page, 'Location-override mismatch-blocks-submit guard. Safe to delete.');
+    await page.locator('input.filepond--browser').setInputFiles(TEST_PHOTO);
+    await waitForPhotoUpload(page);
+
+    await openLocationDetails(page);
+    const latEl = page.locator('input[name="data[lat]"]');
+    const lngEl = page.locator('input[name="data[lng]"]');
+    await latEl.fill('999');
+    await lngEl.fill('999');
+    await lngEl.blur();
+    await expect(latEl).toHaveClass(/location-field--mismatch/);
+
+    await page.locator('.btn-post').evaluate((el) => el.click());
+    await expect(page.locator('.notices')).toHaveCount(0);
+    await expect(page).toHaveURL(/\/post/);
+});
+
 // ── U4: lazy-load boundary — an ordinary GPS-only submit never fetches maplibre-gl ──
 test('an ordinary submit without opening the panel never fetches the maplibre-gl chunk', async ({ page }) => {
     const chunkRequests = [];