feat(dashboard): Enhance dashboard with PageHeader, StatCard, and auth fixes

- Create PageHeader component with title, description, and action slots
- Create StatCard component with trend indicators and icons
- Update dashboard with KPI cards, Quick Actions, and Allocation Preview
- Polish login page with branding and centered layout
- Fix auth redirect: authenticated users accessing /login go to dashboard
- Fix page refresh: auth state persists, no blank page
- Fix sidebar: visible after login, toggle works, state persists
- Fix CSS import: add app.css to layout, fix DaisyUI import path
- Fix breadcrumbs: home icon links to /dashboard
- Add comprehensive E2E and unit tests

Refs: openspec/changes/p03-dashboard-enhancement
Closes: p03-dashboard-enhancement

openspec/config.yaml

@@ -155,7 +155,7 @@ scripts:
 rules:
   # Project-level standing instructions (from decision-log.md)
   all_changes:
-    - Every change must follow SDD+TDD: specs → pending tests → implementation → refactor
+    - "Every change must follow SDD+TDD: specs → pending tests → implementation → refactor"
     - Every spec scenario must have corresponding tests (E2E, API, Unit, Component)
     - Pending tests must be committed before implementation (red phase)
     - Changes must end with code review for style, standards, and security
@@ -177,7 +177,7 @@ rules:
   
   # Workflow Loops
   workflow:
-    - Follow capability-based workflow: Test → Implement → Refactor → Document
+    - "Follow capability-based workflow: Test → Implement → Refactor → Document"
     - Do NOT skip phases - each phase has a specific commit
     - Run full test suite after EACH implementation commit
     - Fix failing tests before moving to next scenario
@@ -188,11 +188,11 @@ rules:
   ui_standards:
     - Use Lucide Svelte for ALL icons (no inline SVGs, no other icon libraries)
     - DaisyUI-first approach - use DaisyUI components before building custom
-    - Sidebar pattern: Collapsible (expanded ↔ collapsed ↔ hidden)
+    - "Sidebar pattern: Collapsible (expanded ↔ collapsed ↔ hidden)"
     - Global month selector in top bar (affects all views)
     - Light mode default, dark mode available via toggle
-    - Table density: Use table-compact for data-heavy views
-    - Reference apps: Obsidian (minimal chrome) + Jira (hierarchical sidebar)
+    - "Table density: Use table-compact for data-heavy views"
+    - "Reference apps: Obsidian (minimal chrome) + Jira (hierarchical sidebar)"
   
   # Component Patterns
   component_patterns:
@@ -210,30 +210,29 @@ rules:
   
   # Accessibility Requirements
   accessibility:
-    - Keyboard navigation: Tab through sidebar, Enter/Space to activate
+    - "Keyboard navigation: Tab through sidebar, Enter/Space to activate"
     - Escape to close mobile drawer
-    - Cmd/Ctrl + \ to toggle sidebar (desktop)
-    - ARIA: aria-expanded on sidebar toggle, aria-current="page" on active nav
+    - "Cmd/Ctrl + \ to toggle sidebar (desktop)"
+    - "ARIA: aria-expanded on sidebar toggle, aria-current='page' on active nav"
     - Focus trap in mobile drawer
     - Focus restored on drawer close
     - All form inputs must have associated labels
   
   # Responsive Design
   responsive:
-    - ≥1280px (xl): Sidebar expanded by default, manual toggle
-    - 1024-1279px (lg): Sidebar collapsed by default, manual toggle
-    - 768-1023px (md): Sidebar hidden, hamburger menu (drawer overlay)
-    - <768px (sm): Sidebar hidden, hamburger menu (drawer overlay)
-    - Mobile drawer: Full-height overlay with backdrop
+    - "≥1280px (xl): Sidebar expanded by default, manual toggle"
+    - "1024-1279px (lg): Sidebar collapsed by default, manual toggle"
+    - "768-1023px (md): Sidebar hidden, hamburger menu (drawer overlay)"
+    - "<768px (sm): Sidebar hidden, hamburger menu (drawer overlay)"
+    - "Mobile drawer: Full-height overlay with backdrop"
     - Close drawer on route change (mobile)
   
   # State Management Patterns
   state_management:
     - Use Svelte stores for UI state only (not business data)
     - Business data comes from API (no client-side caching beyond DaisyUI)
-    - Stores: auth, layout, period
-    - localStorage keys: headroom_access_token, headroom_refresh_token, 
-                         headroom_sidebar_state, headroom_theme
+    - "Stores: auth, layout, period"
+    - "localStorage keys: headroom_access_token, headroom_refresh_token, headroom_sidebar_state, headroom_theme"
     - Store files go in src/lib/stores/
   
   proposal:
@@ -260,7 +259,7 @@ rules:
   
   tasks:
     - Organize by capability (not by layer)
-    - Each capability has 4 phases: Test (Red) → Implement (Green) → Refactor → Document
+    - "Each capability has 4 phases: Test (Red) → Implement (Green) → Refactor → Document"
     - Break implementation into individual scenarios
     - Include explicit test tasks (write pending, enable one by one)
     - Include API documentation updates as tasks