Polish dashboard UX and update README

- Wrap simulation controls in form to prevent page reruns on change
- Fix TempCo test configs to use 2+ temperature points
- Add Installation, Quick Start, and usage examples to README

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

tests/integration/test_e2e.py

@@ -118,6 +118,9 @@ def test_e2e_tempco_characterization(simulation_server: ServerConfig) -> None:
         # Timestamps should be monotonically increasing
         assert measurements_df["timestamp"].is_monotonic_increasing
 
+        # Cleanup: close repository before tempdir cleanup (Windows file locking)
+        repository.close()
+
 
 def test_e2e_server_lifecycle(simulation_server: ServerConfig) -> None:
     """Test simulation server lifecycle management.
@@ -240,17 +243,21 @@ def test_e2e_multiple_test_runs(simulation_server: ServerConfig) -> None:
         test = TempCoTest()
 
         config1 = {
-            "temperatures": [25.0],
+            "temperatures": [0.0, 25.0],  # Need at least 2 points for TempCo
             "input_voltage": 5.0,
             "load_current": 0.1,
             "settle_time": 0.5,
+            "num_samples": 3,
+            "tempco_limit": 100.0,
         }
 
         config2 = {
-            "temperatures": [25.0],
+            "temperatures": [25.0, 50.0],  # Need at least 2 points for TempCo
             "input_voltage": 3.3,
             "load_current": 0.05,
             "settle_time": 0.5,
+            "num_samples": 3,
+            "tempco_limit": 100.0,
         }
 
         run_id1 = runner.run_test(test, instruments, config1, operator="test_user_1")
@@ -277,3 +284,6 @@ def test_e2e_multiple_test_runs(simulation_server: ServerConfig) -> None:
         assert len(all_runs) >= 2
         assert any(r.id == str(run_id1) for r in all_runs)
         assert any(r.id == str(run_id2) for r in all_runs)
+
+        # Cleanup: close repository before tempdir cleanup (Windows file locking)
+        repository.close()