feat(01-01): create Docker scaffold, FastAPI app shell, and sidebar templates

- Dockerfile with python:3.12-slim-bookworm, curl downloads Pico CSS, HTMX, Alpine.js at build time
- docker-compose.yml with imptune_data:/data named volume and restart policy
- requirements.txt with all phase 1-5 dependencies
- imptune/config.py loading DATA_DIR/PORT from env with DB_PATH and DRIVERS_DIR derived paths
- imptune/main.py: FastAPI app with StaticFiles mount, health+pages routers, startup dir creation
- imptune/api/health.py: GET /health returning {"status": "ok"}
- imptune/api/pages.py: GET / returning dashboard.html with sync def handler
- imptune/templates/base.html: data-theme="auto", sidebar with 5 nav sections, /static/ paths only
- imptune/templates/dashboard.html: quick actions + empty state recent activity
- imptune/static/app.css: sidebar layout, active link highlight, quick action buttons

imptune/templates/dashboard.html

@@ -0,0 +1,41 @@
+{% extends "base.html" %}
+
+{% block content %}
+<h1>Dashboard</h1>
+
+<div class="quick-actions">
+  <a href="#" aria-disabled="true" class="btn-action">New Printer</a>
+  <a href="#" aria-disabled="true" class="btn-action">Upload Driver</a>
+  <a href="#" aria-disabled="true" class="btn-action">Export Package</a>
+</div>
+
+<section class="recent-activity">
+  <h2>Recent Activity</h2>
+
+  <div class="activity-section">
+    <h3>Recent Printers</h3>
+    {% if recent_printers %}
+      <ul>
+        {% for printer in recent_printers %}
+          <li>{{ printer.name }} — {{ printer.ip_address }}</li>
+        {% endfor %}
+      </ul>
+    {% else %}
+      <p class="empty-state">No printers configured yet.</p>
+    {% endif %}
+  </div>
+
+  <div class="activity-section">
+    <h3>Recent Packages</h3>
+    {% if recent_packages %}
+      <ul>
+        {% for package in recent_packages %}
+          <li>{{ package }}</li>
+        {% endfor %}
+      </ul>
+    {% else %}
+      <p class="empty-state">No packages exported yet.</p>
+    {% endif %}
+  </div>
+</section>
+{% endblock %}