fix(ui): session-aware landing header, clickable tiles, shell padding and spacing

- .container redefined on Carbon tokens (was Bootstrap's class — pages had
  no edge padding after the Bootstrap removal)
- landing tiles use cds-clickable-tile and — critically — matching closing
  tags: the fingerprint tile was parsed as NESTED inside the cropper tile
  (mismatched </cds-tile>), painting it on top and swallowing clicks
- landing header reflects the active session (user chip + Sign out instead
  of Sign in)
- vertical rhythm: larger panel padding, row gaps and section margins

tools/public/assets/style.css

@@ -18,10 +18,13 @@ body.app {
 
 /* prevent FOUC on web components */
 cds-button:not(:defined), cds-tag:not(:defined), cds-tile:not(:defined),
-cds-inline-notification:not(:defined), cds-toast:not(:defined),
-cds-toast-item:not(:defined), cds-progress-bar:not(:defined) {
+cds-clickable-tile:not(:defined), cds-inline-notification:not(:defined),
+cds-toast:not(:defined), cds-toast-item:not(:defined), cds-progress-bar:not(:defined) {
   visibility: hidden;
 }
+/* Carbon styles the shadow anchor inside tiles, not the host — give the host
+   a real box so grid columns and click targets work correctly. */
+cds-tile, cds-clickable-tile { display: block; }
 
 /* ── header (Carbon ui-shell look) ──────────────────────────────────────── */
 .nav {
@@ -52,12 +55,11 @@ cds-toast-item:not(:defined), cds-progress-bar:not(:defined) {
 }
 
 /* ── layout ─────────────────────────────────────────────────────────────── */
-main.container { flex: 1 0 auto; max-width: none; padding: 0 1rem; width: 100%; }
-main.container > * { max-width: 1136px; margin-left: auto; margin-right: auto; }
-main.container > .narrow { max-width: 560px; }
+.container { width: 100%; max-width: 1136px; margin: 0 auto; padding: 0 1.5rem; }
+main.container { flex: 1 0 auto; padding-top: 1.5rem; padding-bottom: 1.5rem; }
 .narrow { max-width: 560px; }
 .center-v { display: flex; flex-direction: column; justify-content: center; min-height: 70vh; }
-.page-head { margin: 2rem auto 1.25rem; display: flex; align-items: flex-end; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
+.page-head { margin: 1.5rem auto 1.5rem; display: flex; align-items: flex-end; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
 .page-head h1 { font-size: 1.5rem; font-weight: 600; margin: 0; letter-spacing: 0; }
 .page-head .sub { color: var(--cds-text-secondary, #525252); margin: 0.25rem 0 0; font-size: 14px; }
 
@@ -67,7 +69,7 @@ main.container > .narrow { max-width: 560px; }
   border: 1px solid var(--cds-border-subtle, #c6c6c6);
   border-radius: 2px;
 }
-.panel { padding: 1.25rem 1.5rem 1.5rem; margin-bottom: 1rem; }
+.panel { padding: 1.5rem 1.75rem 1.75rem; margin-bottom: 1.25rem; }
 .panel-head { display: flex; align-items: center; gap: 0.6rem; margin-bottom: 1rem; flex-wrap: wrap; }
 .step-chip {
   width: 22px; height: 22px; border-radius: 2px; flex: 0 0 auto;
@@ -82,7 +84,8 @@ main.container > .narrow { max-width: 560px; }
 .hero { padding: 2.5rem 0 1.75rem; }
 .hero h1 { font-size: 1.75rem; font-weight: 600; margin: 0 0 0.35rem; }
 .hero p { color: var(--cds-text-secondary, #525252); max-width: 560px; margin: 0; font-size: 14px; }
-.tool-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 1rem; max-width: 960px; }
+.tool-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; max-width: 960px; }
+@media (max-width: 720px) { .tool-grid { grid-template-columns: 1fr; } }
 .tool-grid cds-tile { height: 100%; }
 .tool-card { display: flex; flex-direction: column; padding: 1.25rem; }
 .tool-card h3 { font-size: 1rem; font-weight: 600; margin: 0.75rem 0 0.3rem; }
@@ -134,10 +137,11 @@ cds-button::part(button) { font-size: 14px; }
 /* ── badges → cds-tag; helper text ──────────────────────────────────────── */
 .faint { color: var(--cds-text-helper, #6f6f6f); font-size: 12px; }
 .muted { color: var(--cds-text-secondary, #525252); }
-.mt-1 { margin-top: 0.75rem; }
-.mt-2 { margin-top: 1.25rem; }
-.row-gap { display: flex; gap: 0.75rem; align-items: center; flex-wrap: wrap; }
+.mt-1 { margin-top: 1rem; }
+.mt-2 { margin-top: 1.5rem; }
+.row-gap { display: flex; gap: 1rem; align-items: center; flex-wrap: wrap; }
 .flex-fill { flex: 1 1 auto; }
+.form-field { margin-bottom: 0.25rem; }
 
 /* ── details grid ───────────────────────────────────────────────────────── */
 .details { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); gap: 0.9rem 1.4rem; margin: 0 0 0.25rem; }