Consolidate duplicated page CSS into app.css, share TestDb type

- Move .page-header/.back-link/.input-invalid/.save-status/.btn-done
  (plus hover/variant rules) into app.css as shared route scaffolding;
  delete per-page scoped copies
- Unify drifted values: page-header padding 1rem -> 1.25rem (routine
  page), empty-state spacing 0.75/1.5rem -> 1/2rem (grocery detail),
  save-status margin -0.25rem applied on both pages, back-link margin
  1.5rem -> 1rem (grocery detail); routine page's large Fait button is
  kept via a .btn-done-lg modifier
- Export TestDb from test-helper and use it in the five db/service
  test files to shrink duplicated fixture scaffolding

1 files changed, 63 insertions, 0 deletions

diff --git a/src/app.css b/src/app.css
index 7b8464f..1c25c93 100644
--- a/src/app.css
+++ b/src/app.css
@@ -212,6 +212,8 @@ button {
 	background: var(--surface);
 	border-radius: 0.75rem;
 	box-shadow: 0 1px 2px var(--shadow);
+	margin-top: 1rem;
+	padding: 2rem;
 }
 
 /* Error */
@@ -398,3 +400,64 @@ button {
 	font-weight: 600;
 	white-space: nowrap;
 }
+
+/* Shared route scaffolding */
+.page-header {
+	display: flex;
+	align-items: center;
+	justify-content: space-between;
+	padding: 1.25rem 0;
+}
+
+.back-link {
+	display: inline-flex;
+	align-items: center;
+	gap: 0.375rem;
+	margin-top: 1rem;
+	color: var(--text-secondary);
+	text-decoration: none;
+	font-size: 0.875rem;
+	font-weight: 500;
+	transition: color 0.2s;
+}
+
+.back-link:hover {
+	color: var(--accent);
+}
+
+.input-invalid {
+	border-color: var(--danger);
+}
+
+.save-status {
+	font-size: 0.875rem;
+	color: var(--success);
+	font-weight: 500;
+	margin-top: -0.25rem;
+	visibility: hidden;
+	opacity: 0;
+	transition: opacity 0.2s ease;
+	min-height: 1.25rem;
+}
+
+.save-status.visible {
+	visibility: visible;
+	opacity: 1;
+}
+
+.btn-done {
+	flex-shrink: 0;
+	padding: 0.5rem 0.875rem;
+	border: none;
+	border-radius: 0.625rem;
+	background: var(--success);
+	color: var(--white);
+	font-size: 0.875rem;
+	font-weight: 500;
+	transition: all 0.2s ease;
+}
+
+.btn-done:hover {
+	filter: brightness(1.05);
+	transform: translateY(-1px);
+}