Refactored installer into modular library structure with improved error handling and logging.

The changes include:
- Split monolithic script into lib/, config/, profiles/, and files/ directories
- Added error handling with cleanup on failure
- Added installation logging to /var/log/arch-install.log
- Added username validation

config/luks.conf

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# luks.conf - LUKS encryption parameters
+#
+# Cryptographic settings for full-disk encryption using LUKS2.
+
+LUKS_TYPE="luks2"
+LUKS_CIPHER="aes-xts-plain64"
+LUKS_HASH="sha512"
+LUKS_KEY_SIZE="512"
+LUKS_PBKDF="argon2id"
+LUKS_PBKDF_ITERATIONS="8"
+LUKS_PBKDF_MEMORY="4194304"
+LUKS_PBKDF_PARALLEL="4"