Modernize frontend with tabs, HTMX, and Tailwind build pipeline

Complete UI overhaul implementing modern design patterns with HTMX for
dynamic updates, proper Tailwind build pipeline, and improved UX.

Build Pipeline:
- Add npm + PostCSS + Tailwind CSS configuration
- Custom design system with brand colors
- Compiled CSS: 27KB (vs 3MB CDN), 99% reduction
- Makefile for unified build commands
- Inter font for improved typography

Tab Interface:
- Separate Tasks tab from Notes tab using HTMX
- Partial page updates without full refreshes
- Tab state management with proper refresh handling
- New endpoints: /tabs/tasks, /tabs/notes, /tabs/refresh

Template Architecture:
- Modular partials system (7 reusable components)
- Cleaner separation of concerns

Empty Board Management:
- Active boards in main 3-column grid
- Empty boards in collapsible section
- Reduces visual clutter

Visual Design Enhancements:
- Inter font, brand color accents
- Improved typography hierarchy and spacing
- Enhanced card styling with hover effects

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

1 files changed, 12 insertions, 0 deletions

diff --git a/web/templates/partials/error-banner.html b/web/templates/partials/error-banner.html
new file mode 100644
index 0000000..eb4c08d
--- /dev/null
+++ b/web/templates/partials/error-banner.html
@@ -0,0 +1,12 @@
+{{define "error-banner"}}
+{{if .Errors}}
+<div class="bg-red-100 border border-red-400 text-red-700 px-4 py-3 rounded-lg mb-6">
+    <p class="font-bold">Errors:</p>
+    <ul class="list-disc list-inside">
+        {{range .Errors}}
+        <li>{{.}}</li>
+        {{end}}
+    </ul>
+</div>
+{{end}}
+{{end}}