Put the Save name button beside the input, fit to its width

Matches the status 'Add' form immediately below it: renamed the
shared row layout from .status-list__new to .field-row (it now backs
both forms) and switched the project name form to it -- input grows,
button sits to its right sized to its own label instead of stretching
full width underneath. Dropped the visible 'Name' label in favour of
a placeholder + aria-label, mirroring the status form exactly.

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

web/src/style.css

@@ -749,13 +749,16 @@ h1 {
   cursor: not-allowed;
 }
 
-.status-list__new {
+/* An input with its submit button beside it (fit to its label text) rather
+   than below (full width, the plain .form pattern) -- the status "Add" form
+   and the project name form both use it. */
+.field-row {
   display: flex;
   gap: 0.4rem;
   margin-top: 0.75rem;
 }
 
-.status-list__new input {
+.field-row input {
   flex: 1;
   min-width: 0;
   font: inherit;
@@ -767,7 +770,7 @@ h1 {
   color: var(--text);
 }
 
-.status-list__new button[type='submit'] {
+.field-row button[type='submit'] {
   flex: none;
   padding: 0.4rem 0.7rem;
   font-size: 0.9rem;