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

src/py_dvt_ate/app/dashboard/app.py

@@ -233,63 +233,72 @@ def display_controls() -> None:
 
     st.sidebar.divider()
 
-    # Time multiplier
-    st.sidebar.subheader("Simulation Speed")
-    st.sidebar.select_slider(
-        "Time Multiplier",
-        options=[1, 2, 5, 10, 20, 50, 100],
-        value=10,
-        format_func=lambda x: f"{x}x",
-        key="time_multiplier",
-    )
-    st.sidebar.caption(
-        f"1 real second = {st.session_state.get('time_multiplier', 10)} simulation seconds"
-    )
+    # Parameter Controls - wrapped in form to prevent reruns on every change
+    with st.sidebar.form("parameter_controls"):
+        st.subheader("Simulation Parameters")
+        st.caption("💡 Change parameters below, then click Apply to update the simulation")
 
-    st.sidebar.divider()
+        # Time multiplier
+        time_multiplier = st.select_slider(
+            "Time Multiplier",
+            options=[1, 2, 5, 10, 20, 50, 100],
+            value=st.session_state.get("time_multiplier", 10),
+            format_func=lambda x: f"{x}x",
+        )
+        st.caption(f"1 real second = {time_multiplier} simulation seconds")
 
-    # Temperature setpoint
-    st.sidebar.subheader("Thermal Chamber")
-    st.sidebar.slider(
-        "Temperature Setpoint (C)",
-        min_value=-40.0,
-        max_value=125.0,
-        value=25.0,
-        step=5.0,
-        key="temp_setpoint",
-    )
+        st.divider()
 
-    st.sidebar.divider()
+        # Temperature setpoint
+        st.markdown("**Thermal Chamber**")
+        temp_setpoint = st.slider(
+            "Temperature Setpoint (C)",
+            min_value=-40.0,
+            max_value=125.0,
+            value=st.session_state.get("temp_setpoint", 25.0),
+            step=5.0,
+        )
 
-    # Power supply controls
-    st.sidebar.subheader("Power Supply")
-    st.sidebar.slider(
-        "Input Voltage (V)",
-        min_value=0.0,
-        max_value=12.0,
-        value=5.0,
-        step=0.1,
-        key="input_voltage",
-    )
+        st.divider()
 
-    st.sidebar.toggle(
-        "Output Enabled",
-        value=False,
-        key="output_enabled",
-    )
+        # Power supply controls
+        st.markdown("**Power Supply**")
+        input_voltage = st.slider(
+            "Input Voltage (V)",
+            min_value=0.0,
+            max_value=12.0,
+            value=st.session_state.get("input_voltage", 5.0),
+            step=0.1,
+        )
 
-    st.sidebar.divider()
+        output_enabled = st.toggle(
+            "Output Enabled",
+            value=st.session_state.get("output_enabled", False),
+        )
 
-    # Load controls
-    st.sidebar.subheader("Electronic Load")
-    st.sidebar.slider(
-        "Load Current (mA)",
-        min_value=0.0,
-        max_value=500.0,
-        value=100.0,
-        step=10.0,
-        key="load_current",
-    )
+        st.divider()
+
+        # Load controls
+        st.markdown("**Electronic Load**")
+        load_current = st.slider(
+            "Load Current (mA)",
+            min_value=0.0,
+            max_value=500.0,
+            value=st.session_state.get("load_current", 100.0),
+            step=10.0,
+        )
+
+        # Apply button
+        submitted = st.form_submit_button("✅ Apply Changes", type="primary", use_container_width=True)
+
+        if submitted:
+            # Update session state with new values
+            st.session_state.time_multiplier = time_multiplier
+            st.session_state.temp_setpoint = temp_setpoint
+            st.session_state.input_voltage = input_voltage
+            st.session_state.output_enabled = output_enabled
+            st.session_state.load_current = load_current
+            st.rerun()
 
 
 @st.fragment(run_every=0.1)
@@ -613,13 +622,13 @@ def test_execution_page() -> None:
                 runner: TestRunner = st.session_state.test_runner
                 instruments: InstrumentSet = st.session_state.instruments
 
-                # Connect instruments before running test
+                # Instruments should already be connected from dashboard startup
+                # Just verify they're connected
                 try:
-                    instruments.chamber.transport.connect()  # type: ignore[attr-defined]
-                    instruments.psu.transport.connect()  # type: ignore[attr-defined]
-                    instruments.dmm.transport.connect()  # type: ignore[attr-defined]
+                    # Quick connectivity check
+                    _ = instruments.chamber.get_temperature()
                 except Exception as e:
-                    st.error(f"Failed to connect to instruments: {e}")
+                    st.error(f"Instruments not available: {e}")
                     st.session_state.test_running = False
                     st.stop()
 

src/py_dvt_ate/data/repository.py

@@ -74,6 +74,9 @@ class ITestRepository(ABC):
     def get_all_runs(self) -> list[TestRun]:
         """Retrieve all test runs, ordered by started_at descending."""
 
+    def close(self) -> None:
+        """Close repository and release resources. Optional to implement."""
+
 
 class SQLiteRepository(ITestRepository):
     """SQLite-based repository for test data.
@@ -400,3 +403,13 @@ class SQLiteRepository(ITestRepository):
                 )
                 for row in rows
             ]
+
+    def close(self) -> None:
+        """Close repository and release resources.
+
+        SQLite connections are managed via context managers and auto-close.
+        This method performs explicit cleanup for Windows file handle issues.
+        """
+        # Force garbage collection to release any lingering connections
+        import gc
+        gc.collect()