Use Radar Eye logo in the app header + README

- App: top-bar brand mark is now the Radar Eye (drawable/vigil_logo.xml) instead of a generic shield.
- README: centered logo header (docs/logo.png, rendered from docs/logo.svg).
Release 0.1.7.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0187UiEtasyowhEBYs6s9iF5

app/src/main/kotlin/org/soulstone/vigil/ui/MainScreen.kt

@@ -9,7 +9,9 @@ import androidx.compose.material3.FilledTonalButton
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.ui.graphics.lerp
+import androidx.compose.ui.res.painterResource
 import org.soulstone.vigil.service.ScanService
+import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
@@ -70,6 +72,7 @@ import org.soulstone.vigil.BuildConfig
 import org.soulstone.vigil.data.db.TrackerEntity
 import org.soulstone.vigil.model.Sensitivity
 import org.soulstone.vigil.model.TrackerEcosystem
+import org.soulstone.vigil.R
 import org.soulstone.vigil.model.TrackerStatus
 import org.soulstone.vigil.ui.theme.VigilGreen
 import org.soulstone.vigil.ui.theme.VigilPeach
@@ -106,7 +109,11 @@ fun MainScreen(
             TopAppBar(
                 title = {
                     Row(verticalAlignment = Alignment.CenterVertically) {
-                        Icon(Icons.Filled.Shield, null, tint = MaterialTheme.colorScheme.primary)
+                        Image(
+                            painterResource(R.drawable.vigil_logo),
+                            contentDescription = null,
+                            modifier = Modifier.size(26.dp)
+                        )
                         Spacer(Modifier.size(8.dp))
                         Text("VIGIL", fontWeight = FontWeight.Bold)
                     }

app/src/main/res/drawable/vigil_logo.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- VIGIL wordmark glyph (Radar Eye), tight-cropped for in-app use (top bar). -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="48dp"
+    android:height="48dp"
+    android:viewportWidth="48"
+    android:viewportHeight="48">
+    <path
+        android:pathData="M4,24 Q24,8 44,24 Q24,40 4,24 Z"
+        android:strokeColor="#89B4FA"
+        android:strokeWidth="3"
+        android:strokeLineJoin="round"
+        android:fillColor="#00000000" />
+    <path
+        android:pathData="M24,24 m-7.5,0 a7.5,7.5 0 1,0 15,0 a7.5,7.5 0 1,0 -15,0"
+        android:strokeColor="#89B4FA"
+        android:strokeWidth="2.4"
+        android:fillColor="#00000000" />
+    <path
+        android:pathData="M24,24 m-4.4,0 a4.4,4.4 0 1,0 8.8,0 a4.4,4.4 0 1,0 -8.8,0"
+        android:strokeColor="#B4BEFE"
+        android:strokeWidth="2"
+        android:fillColor="#00000000" />
+    <path
+        android:pathData="M24,24 m-2.2,0 a2.2,2.2 0 1,0 4.4,0 a2.2,2.2 0 1,0 -4.4,0"
+        android:fillColor="#A6E3A1" />
+</vector>