docs: Update project specs and align statuses

- Add Timber to technical decisions in tech_spec.txt
- Update feature statuses to 'backend_implemented' in tech_spec.txt
- Update UI component statuses to 'needs_review' in project_structure.txt

data/src/main/java/com/homebox/lens/data/api/mapper/TokenMapper.kt

@@ -0,0 +1,4 @@
+package com.homebox.lens.data.api.mapper
+
+class TokenMapper {
+}

data/src/main/java/com/homebox/lens/data/api/model/LoginRequest.kt

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+// [PACKAGE] com.homebox.lens.data.api.model
+// [FILE] LoginRequest.kt
+// [SEMANTICS] dto, network, serialization, authentication
+
+package com.homebox.lens.data.api
+
+import com.squareup.moshi.Json
+import com.squareup.moshi.JsonClass
+
+/**
+ * [ENTITY: DataClass('LoginRequest')]
+ * [CONTRACT]
+ * DTO (Data Transfer Object) для запроса на аутентификацию.
+ * @property username Имя пользователя.
+ * @property password Пароль пользователя.
+ * @invariant Свойства не должны быть пустыми.
+ */
+@JsonClass(generateAdapter = true)
+data class LoginRequest(
+    @Json(name = "username") val username: String,
+    @Json(name = "password") val password: String
+) {
+    init {
+        // [INVARIANT_CHECK]
+        require(username.isNotBlank()) { "[INVARIANT_FAILED] Username cannot be blank." }
+        require(password.isNotBlank()) { "[INVARIANT_FAILED] Password cannot be blank." }
+    }
+}
+// [END_FILE_LoginRequest.kt]

data/src/main/java/com/homebox/lens/data/repository/EncryptedPreferencesWrapper.kt

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+package com.homebox.lens.data.repository
+
+class EncryptedPreferencesWrapper {
+}

data/src/main/java/com/homebox/lens/data/security/CryptoManager.kt

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+package com.homebox.lens.data.security
+
+class CryptoManager {
+}