fix(school-detail): float Compare over the map band, not the school name

Regression from d4d9ae5 (map-blended hero): .headerHasMap .actions was
absolutely positioned intending to float over the map, but its containing
block was .headerContent — made position:relative in the same commit — so
top:14px anchored it to the title block below the map. On mobile the H1
spans the full width and the legacy '.actions { width: 100% }' rule still
applied, stretching the glassy button across the school name and leaving
a ~6px legible sliver between it and the map fade.

Anchor .actions to .header by moving position:relative/z-index:3 from
.headerContent to .titleSection (the element that actually needs to sit
above the fade), and set width:auto on the floating variant so the mobile
full-width rule can't reach it. Applied to both detail views.

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

nextjs-app/components/SchoolDetailView.module.css

@@ -53,6 +53,12 @@
 .headerHasMap .headerContent {
     padding-top: 0;
     margin-top: -0.5rem;
+}
+
+/* The title (not the whole content row) rises above the map fade. Keeping
+   .headerContent unpositioned matters: .actions must anchor to .header so it
+   floats over the map band, not over the title. */
+.headerHasMap .titleSection {
     position: relative;
     z-index: 3;
 }
@@ -63,6 +69,9 @@
     right: 14px;
     z-index: 6;
     margin: 0;
+    /* Beat the mobile `.actions { width: 100% }` rule — a floating button
+       must never stretch across the title. */
+    width: auto;
 }
 
 .headerHasMap .actions .btnAdd {

nextjs-app/components/SecondarySchoolDetailView.module.css

@@ -53,6 +53,12 @@
 .headerHasMap .headerContent {
     padding-top: 0;
     margin-top: -0.5rem;
+}
+
+/* The title (not the whole content row) rises above the map fade. Keeping
+   .headerContent unpositioned matters: .actions must anchor to .header so it
+   floats over the map band, not over the title. */
+.headerHasMap .titleSection {
     position: relative;
     z-index: 3;
 }
@@ -63,6 +69,9 @@
     right: 14px;
     z-index: 6;
     margin: 0;
+    /* Beat the mobile `.actions { width: 100% }` rule — a floating button
+       must never stretch across the title. */
+    width: auto;
 }
 
 .headerHasMap .actions .btnAdd {