Move the new-project form into the dashboard grid as a tile

It now sits last in .dashboard__grid, styled like a project-card (dashed
border to read as an action rather than a project) instead of as a
separate form below the grid. Relabel it 'Create a project' and add a
'Name' placeholder to the input.

Also drop the now-redundant 'no projects yet' empty-state message --
the grid always renders since the create tile lives inside it.

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

web/src/style.css

@@ -360,6 +360,25 @@ h1 {
   font-size: 0.85rem;
 }
 
+.project-card--new {
+  border-style: dashed;
+}
+
+.project-card--new label {
+  display: grid;
+  gap: 0.3rem;
+  font-size: 0.9rem;
+}
+
+.project-card--new input {
+  padding: 0.55rem 0.7rem;
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  background: var(--bg);
+  color: var(--text);
+  font-size: 1rem;
+}
+
 /* --- project detail: cards ------------------------------------------ */
 
 .cards {
@@ -743,7 +762,6 @@ h1 {
   margin: 1.25rem 0;
 }
 
-.form--new-project,
 .form--new-card {
   margin-top: 1.5rem;
   padding-top: 1.25rem;