Sort and look up text columns case-insensitively

Add COLLATE NOCASE on every text content column (names, owners, vendors,
device types, MAC addresses, notification titles/bodies/types, event
types) so DESC-by-name lists no longer order "iPad" before "Lutron".
Normalize MAC addresses to lowercase at the DB layer so the now
case-insensitive primary key cannot accept duplicate-looking rows.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/database_migrations/01-initial_structure/up.sql

@@ -1,18 +1,18 @@
 CREATE TABLE devices(
-    mac_address TEXT PRIMARY KEY,
+    mac_address TEXT PRIMARY KEY COLLATE NOCASE,
     ipv4_address TEXT NOT NULL,
-    vendor TEXT,
+    vendor TEXT COLLATE NOCASE,
     last_seen TEXT NOT NULL,
     is_registered INTEGER NOT NULL,
-    owner TEXT,
-    device_type TEXT
+    owner TEXT COLLATE NOCASE,
+    device_type TEXT COLLATE NOCASE
 );
 
 CREATE TABLE notifications(
     id INTEGER PRIMARY KEY,
     created_on TEXT NOT NULL,
-    notification_type TEXT NOT NULL,
-    title TEXT NOT NULL,
-    body TEXT,
+    notification_type TEXT NOT NULL COLLATE NOCASE,
+    title TEXT NOT NULL COLLATE NOCASE,
+    body TEXT COLLATE NOCASE,
     is_new INTEGER NOT NULL
 );

backend/database_migrations/02-add_mac_address_to_notifications/up.sql

@@ -1 +1 @@
-ALTER TABLE notifications ADD COLUMN mac_address TEXT;
+ALTER TABLE notifications ADD COLUMN mac_address TEXT COLLATE NOCASE;

backend/database_migrations/03-add_device_events/up.sql

@@ -1,8 +1,8 @@
 CREATE TABLE device_events(
     id INTEGER PRIMARY KEY,
-    mac_address TEXT NOT NULL,
+    mac_address TEXT NOT NULL COLLATE NOCASE,
     created_on TEXT NOT NULL,
-    event_type TEXT NOT NULL,
+    event_type TEXT NOT NULL COLLATE NOCASE,
     ipv4_address TEXT NOT NULL,
-    vendor TEXT NOT NULL
+    vendor TEXT NOT NULL COLLATE NOCASE
 );

backend/database_migrations/08-add_name_to_devices/up.sql

@@ -1 +1 @@
-ALTER TABLE devices ADD COLUMN name TEXT;
+ALTER TABLE devices ADD COLUMN name TEXT COLLATE NOCASE;