Add drawer menu with flat structure, unified panel styling, Room/SQLCipher setup

app/src/main/java/com/mistral/chat/data/Profile.kt

@@ -0,0 +1,15 @@
+package com.mistral.chat.data
+
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = "profiles")
+data class Profile(
+    @PrimaryKey(autoGenerate = true)
+    val id: Long = 0,
+    val name: String,
+    val bio: String = "",
+    val preferences: String = "",
+    val createdAt: Long = System.currentTimeMillis(),
+    val updatedAt: Long = System.currentTimeMillis()
+)