feat(mindmachine): implement Android MVP app scaffold, session flows, safety gating, and tests

app/src/test/java/com/mindmachine/mvp/PresetDefaultsTest.kt

@@ -0,0 +1,28 @@
+package com.mindmachine.mvp
+
+import com.mindmachine.mvp.domain.Presets
+import com.mindmachine.mvp.domain.VisualPattern
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class PresetDefaultsTest {
+    @Test
+    fun mvp_has_exactly_three_presets_with_spec_defaults() {
+        assertEquals(3, Presets.builtIn.size)
+        val relax = Presets.builtIn.first { it.id == "relax" }
+        val focus = Presets.builtIn.first { it.id == "focus" }
+        val sleep = Presets.builtIn.first { it.id == "sleep" }
+
+        assertEquals(10 * 60, relax.defaultDurationSec)
+        assertEquals(VisualPattern.PULSE, relax.visualPatternType)
+        assertEquals(6f, relax.blinkFrequencyHz)
+
+        assertEquals(15 * 60, focus.defaultDurationSec)
+        assertEquals(VisualPattern.FLASH, focus.visualPatternType)
+        assertEquals(10f, focus.blinkFrequencyHz)
+
+        assertEquals(20 * 60, sleep.defaultDurationSec)
+        assertEquals(VisualPattern.PULSE, sleep.visualPatternType)
+        assertEquals(3f, sleep.blinkFrequencyHz)
+    }
+}

app/src/test/java/com/mindmachine/mvp/SessionValidatorTest.kt

@@ -0,0 +1,46 @@
+package com.mindmachine.mvp
+
+import com.mindmachine.mvp.domain.SessionMode
+import com.mindmachine.mvp.domain.VisualPattern
+import com.mindmachine.mvp.domain.SessionConfig
+import com.mindmachine.mvp.session.SessionValidator
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Test
+
+class SessionValidatorTest {
+    private val valid = SessionConfig(
+        presetId = "relax",
+        durationSec = 600,
+        mode = SessionMode.AUDIO_VISUAL,
+        visualPatternType = VisualPattern.PULSE,
+        blinkFrequencyHz = 6f,
+        intensityPercent = 50,
+        carrierFrequencyHz = 200f,
+        binauralDifferenceHz = 6f,
+    )
+
+    @Test
+    fun valid_with_headset_passes() {
+        assertNull(SessionValidator.validate(valid, headsetAvailable = true))
+    }
+
+    @Test
+    fun audio_without_headset_is_blocked() {
+        val error = SessionValidator.validate(valid, headsetAvailable = false)
+        assertEquals("Stereo headphones are required for binaural audio. Connect headphones or switch to Visual-only.", error)
+    }
+
+    @Test
+    fun visual_only_without_headset_passes() {
+        assertNull(SessionValidator.validate(valid.copy(mode = SessionMode.VISUAL_ONLY), headsetAvailable = false))
+    }
+
+    @Test
+    fun out_of_range_values_are_blocked() {
+        assertEquals("Duration must be 1 to 30 minutes.", SessionValidator.validate(valid.copy(durationSec = 59), true))
+        assertEquals("Blink frequency must be 1.0 to 20.0 Hz.", SessionValidator.validate(valid.copy(blinkFrequencyHz = 21f), true))
+        assertEquals("Carrier frequency must be 80 to 400 Hz.", SessionValidator.validate(valid.copy(carrierFrequencyHz = 79f), true))
+        assertEquals("Binaural difference must be 0.5 to 20 Hz.", SessionValidator.validate(valid.copy(binauralDifferenceHz = 0.1f), true))
+    }
+}