feat(02-02): add driver upload endpoint with INF parsing and dedup

- POST /drivers/upload: validates ZIP, parses INF, persists via DriverStore + Peewee
- SHA256 dedup: get_or_create prevents duplicate Driver records
- GET /drivers route added to pages.py with driver_data context
- drivers.router registered in main.py
- drivers.html template with HTMX upload form
- partials/driver_list.html HTMX target with select dropdown and unused-file notice
- Fixed conftest client fixture to use context manager (triggers lifespan/init_db)
- [Rule 3] conftest: TestClient context manager required for lifespan trigger
- [Rule 1] drivers.py: dynamic DRIVERS_DIR read so monkeypatch works in tests

imptune/templates/partials/driver_list.html

@@ -0,0 +1,50 @@
+<div id="driver-list">
+  {% if parsed is defined and parsed.unused_files %}
+  <p class="notice">
+    {{ parsed.unused_files | length }} file(s) may be unused (not referenced by the INF):
+    <details>
+      <summary>Show unused files</summary>
+      <ul>
+        {% for f in parsed.unused_files %}
+        <li>{{ f }}</li>
+        {% endfor %}
+      </ul>
+    </details>
+  </p>
+  {% endif %}
+
+  {% if driver_data %}
+  <table>
+    <thead>
+      <tr>
+        <th>Filename</th>
+        <th>Driver Name(s)</th>
+        <th>Architecture</th>
+        <th>Uploaded</th>
+      </tr>
+    </thead>
+    <tbody>
+      {% for item in driver_data %}
+      <tr>
+        <td>{{ item.driver.original_filename }}</td>
+        <td>
+          {% if item.names %}
+          <select aria-label="Driver names">
+            {% for name in item.names %}
+            <option>{{ name }}</option>
+            {% endfor %}
+          </select>
+          {% else %}
+          <em>Unknown</em>
+          {% endif %}
+        </td>
+        <td>{{ item.driver.architecture or "Unknown" }}</td>
+        <td>{{ item.driver.uploaded_at }}</td>
+      </tr>
+      {% endfor %}
+    </tbody>
+  </table>
+  {% else %}
+  <p>No drivers uploaded yet.</p>
+  {% endif %}
+</div>