style(web): slim NewProjectPanel form (title, fidelity, buttons, ds-picker)

The form inside the new white card felt overweight against the
compacted layout from the previous commits — fidelity cards were
~133px tall, the Create button + Open-folder secondary button both
had ~11px symmetric padding, the design-system trigger had a 32px
avatar in a 55px-tall row. Slim every element so the card reads as a
focused form, not a stack of beefy buttons.

Title:
- \`.newproj-title\` font \`14px / 600 → 13px / 550\`. Still
  visibly the section heading but no longer competing with the
  serif brand title above.

Fidelity:
- \`.fidelity-thumb { aspect-ratio: 12/7 → 16/7 }\`. The previous
  aspect made cards taller than they needed to be in the narrow
  sidebar column.
- \`.fidelity-card { gap: 8 → 6, padding: 10/10/12 → 8/8/10 }\`.
  Combined with the thumb aspect change, card height drops from
  ~133px → ~102px (visually close to the Claude Design reference
  while keeping the same content).

Primary / secondary buttons:
- \`.newproj-create\` padding \`11px (symmetric) → 8px 11px\`,
  margin-top \`4 → 2\` — primary CTA no longer towers over the
  fidelity cards above it.
- \`.newproj-import\` padding \`10px → 6px 10px\` — the secondary
  "Import Claude Design ZIP" button feels like an alt option, not
  a peer of Create.

Design system trigger:
- \`.ds-picker-trigger\` gap \`10 → 8\`, padding \`8/10 → 6/10\`.
- \`.ds-picker-title\` font \`13 → 12.5\` so name + subtitle stay
  legible in the slimmer row without overflowing the column.
- \`.ds-avatar\` width/height \`32 → 26\`, border-radius \`6 → 5\`.
  The thumbnail was the dominant element in the row; shrinking it
  pulls the row height from ~55px → ~50px.

Footer disclaimer:
- \`.newproj-footer\` padding-top \`0 → 12px\`. The "Only you can
  see your project by default." line was butting against the card
  bottom; 12px of air separates the disclaimer (page-bg context)
  from the card (panel-bg context) cleanly.

apps/web/src/index.css

@@ -3869,8 +3869,8 @@ code {
 }
 .newproj-title {
   margin: 0;
-  font-size: 14px;
+  font-size: 13px;
-  font-weight: 600;
+  font-weight: 550;
   display: flex;
   align-items: center;
   gap: 8px;
@@ -4137,8 +4137,8 @@ code {
   justify-content: center;
   gap: 8px;
   width: 100%;
-  padding: 11px;
+  padding: 8px 11px;
-  margin-top: 4px;
+  margin-top: 2px;
   font-size: 13px;
   border-radius: var(--radius-sm);
 }
@@ -4148,7 +4148,7 @@ code {
   justify-content: center;
   gap: 8px;
   width: 100%;
-  padding: 10px;
+  padding: 6px 10px;
   font-size: 12.5px;
   border-radius: var(--radius-sm);
 }
@@ -4183,7 +4183,7 @@ code {
   opacity: 0.7;
 }
 .newproj-footer {
-  padding: 0 24px 16px;
+  padding: 12px 24px 16px;
   font-size: 11px;
   color: var(--text-muted);
   text-align: center;
@@ -4201,8 +4201,8 @@ code {
   display: flex;
   flex-direction: column;
   align-items: stretch;
-  gap: 8px;
+  gap: 6px;
-  padding: 10px 10px 12px;
+  padding: 8px 8px 10px;
   background: var(--bg-panel);
   border: 1px solid var(--border);
   border-radius: var(--radius-sm);
@@ -4219,7 +4219,7 @@ code {
 .fidelity-thumb {
   display: block;
   width: 100%;
-  aspect-ratio: 12 / 7;
+  aspect-ratio: 16 / 7;
   border-radius: 4px;
   overflow: hidden;
   background: var(--bg-subtle);
@@ -4515,9 +4515,9 @@ code {
 .ds-picker-trigger {
   display: flex;
   align-items: center;
-  gap: 10px;
+  gap: 8px;
   width: 100%;
-  padding: 8px 10px;
+  padding: 6px 10px;
   background: var(--bg-panel);
   border: 1px solid var(--border);
   border-radius: var(--radius-sm);
@@ -4541,7 +4541,7 @@ code {
   display: inline-flex;
   align-items: center;
   gap: 6px;
-  font-size: 13px;
+  font-size: 12.5px;
   font-weight: 500;
   color: var(--text);
   overflow: hidden;
@@ -4575,9 +4575,9 @@ code {
 .ds-avatar {
   position: relative;
   flex: none;
-  width: 32px;
+  width: 26px;
-  height: 32px;
+  height: 26px;
-  border-radius: 6px;
+  border-radius: 5px;
   overflow: hidden;
   border: 1px solid var(--border);
   background: var(--bg-panel);