Use configured timezone throughout codebase

- Add config/timezone.go with timezone utilities:
  - SetDisplayTimezone(), GetDisplayTimezone()
  - Now(), Today() - current time/date in display TZ
  - ParseDateInDisplayTZ(), ToDisplayTZ() - parsing helpers

- Initialize timezone at startup in main.go

- Update all datetime logic to use configured timezone:
  - handlers/handlers.go - all time.Now() calls
  - handlers/timeline.go - date parsing
  - handlers/timeline_logic.go - now calculation
  - models/atom.go - ComputeUIFields()
  - models/timeline.go - ComputeDaySection()
  - api/plantoeat.go - meal date parsing
  - api/todoist.go - due date parsing
  - api/trello.go - due date parsing

This ensures all dates/times display correctly regardless
of server timezone setting.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 126 insertions, 0 deletions

diff --git a/internal/api/plantoeat_test.go b/internal/api/plantoeat_test.go
new file mode 100644
index 0000000..50ad4ed
--- /dev/null
+++ b/internal/api/plantoeat_test.go
@@ -0,0 +1,126 @@
+package api
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestParseShoppingListHTML(t *testing.T) {
+	// Sample HTML structure matching PlanToEat's shopping list
+	html := `
+	<div id="shopping_items" data-total-items="3">
+		<div id="store-0" class="store" data-store-id="0">
+			<div class="store_heading">
+				<h4 class="store_name">Costco (3)</h4>
+			</div>
+			<table>
+				<tr>
+					<td class="column">
+						<div class="category-box" id="cat01_350">
+							<p class="category-title"><span>Baking</span></p>
+							<ul class="ingredients">
+								<li class="sli noselect i493745871" data-store-id="0">
+									<label class="checkbox-label">
+										<input type="checkbox" name="items[493745871]" value="493745871">
+										<strong>Olive oil</strong> <span class="quan">2 tablespoons</span>
+									</label>
+								</li>
+								<li class="sli noselect i493745872 checked" data-store-id="0">
+									<label class="checkbox-label">
+										<input type="checkbox" name="items[493745872]" value="493745872" checked>
+										<strong>Flour</strong> <span class="quan">1 cup</span>
+									</label>
+								</li>
+							</ul>
+						</div>
+						<div class="category-box" id="cat01_347">
+							<p class="category-title"><span>Meat</span></p>
+							<ul class="ingredients">
+								<li class="sli noselect i493745889" data-store-id="0">
+									<label class="checkbox-label">
+										<input type="checkbox" name="items[493745889]" value="493745889">
+										<strong>Ground beef</strong> <span class="quan">1 pound</span>
+									</label>
+								</li>
+							</ul>
+						</div>
+					</td>
+				</tr>
+			</table>
+		</div>
+	</div>`
+
+	items, err := parseShoppingListHTML(strings.NewReader(html))
+	if err != nil {
+		t.Fatalf("parseShoppingListHTML failed: %v", err)
+	}
+
+	if len(items) != 3 {
+		t.Errorf("Expected 3 items, got %d", len(items))
+	}
+
+	// Check first item
+	if items[0].Name != "Olive oil" {
+		t.Errorf("Expected first item name 'Olive oil', got '%s'", items[0].Name)
+	}
+	if items[0].Quantity != "2 tablespoons" {
+		t.Errorf("Expected quantity '2 tablespoons', got '%s'", items[0].Quantity)
+	}
+	if items[0].Category != "Baking" {
+		t.Errorf("Expected category 'Baking', got '%s'", items[0].Category)
+	}
+	if items[0].Store != "Costco" {
+		t.Errorf("Expected store 'Costco', got '%s'", items[0].Store)
+	}
+	if items[0].ID != "493745871" {
+		t.Errorf("Expected ID '493745871', got '%s'", items[0].ID)
+	}
+	if items[0].Checked {
+		t.Error("Expected first item to not be checked")
+	}
+
+	// Check checked item
+	if !items[1].Checked {
+		t.Error("Expected second item to be checked")
+	}
+
+	// Check item from different category
+	if items[2].Name != "Ground beef" {
+		t.Errorf("Expected 'Ground beef', got '%s'", items[2].Name)
+	}
+	if items[2].Category != "Meat" {
+		t.Errorf("Expected category 'Meat', got '%s'", items[2].Category)
+	}
+}
+
+func TestParseShoppingListHTML_EmptyList(t *testing.T) {
+	html := `<div id="shopping_items" data-total-items="0"></div>`
+
+	items, err := parseShoppingListHTML(strings.NewReader(html))
+	if err != nil {
+		t.Fatalf("parseShoppingListHTML failed: %v", err)
+	}
+
+	if len(items) != 0 {
+		t.Errorf("Expected 0 items for empty list, got %d", len(items))
+	}
+}
+
+func TestCleanQuantity(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"1 cup", "1 cup"},
+		{"2  tablespoons", "2 tablespoons"},
+		{"1\u00a0pound", "1 pound"},
+		{"  3 oz  ", "3 oz"},
+	}
+
+	for _, tt := range tests {
+		result := cleanQuantity(tt.input)
+		if result != tt.expected {
+			t.Errorf("cleanQuantity(%q) = %q, want %q", tt.input, result, tt.expected)
+		}
+	}
+}