refactor(ui): Lucide migration unit 2 — Icons.* -> LucideIcons.* sweep (#60)

Mechanical sweep across 30 files: every Material Icons.* replaced with
the signed-off Lucide equivalent + a flutter_lucide import per file.
Zero Material Icons.* remain in lib/; no unused imports.

Judgment-call mappings: album->disc_3, library_music->library_big,
playlist_play->list_video, graphic_eq->audio_lines,
system_update->download, restore->archive_restore,
download_done->circle_check_big.

track_actions_sheet like menu row: collapsed `liked ? favorite :
favorite_border` to a single LucideIcons.heart (the row's Like/Unlike
text label conveys state). Icon-only LikeButton + the notification keep
the filled-vs-outline shape per the design decision.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

flutter_client/lib/player/now_playing_screen.dart

@@ -2,6 +2,7 @@ import 'dart:io';
 
 import 'package:audio_service/audio_service.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_lucide/flutter_lucide.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
@@ -376,13 +377,13 @@ class _TopBar extends StatelessWidget {
         padding: const EdgeInsets.symmetric(horizontal: 4),
         child: Row(children: [
           IconButton(
-            icon: Icon(Icons.expand_more, color: fs.parchment),
+            icon: Icon(LucideIcons.chevron_down, color: fs.parchment),
             tooltip: 'Close',
             onPressed: () => Navigator.of(context).maybePop(),
           ),
           const Spacer(),
           IconButton(
-            icon: Icon(Icons.queue_music, color: fs.parchment),
+            icon: Icon(LucideIcons.list_music, color: fs.parchment),
             tooltip: 'Queue',
             onPressed: () => GoRouter.of(context).push('/queue'),
           ),
@@ -535,13 +536,13 @@ class _PrimaryControls extends StatelessWidget {
       children: [
         IconButton(
           iconSize: 36,
-          icon: Icon(Icons.skip_previous, color: fs.parchment),
+          icon: Icon(LucideIcons.skip_back, color: fs.parchment),
           onPressed: () => ref.read(audioHandlerProvider).skipToPrevious(),
         ),
         IconButton(
           iconSize: 72,
           icon: Icon(
-            isPlaying ? Icons.pause_circle_filled : Icons.play_circle_filled,
+            isPlaying ? LucideIcons.circle_pause : LucideIcons.circle_play,
             color: fs.accent,
           ),
           onPressed: () {
@@ -555,7 +556,7 @@ class _PrimaryControls extends StatelessWidget {
         ),
         IconButton(
           iconSize: 36,
-          icon: Icon(Icons.skip_next, color: fs.parchment),
+          icon: Icon(LucideIcons.skip_forward, color: fs.parchment),
           onPressed: () => ref.read(audioHandlerProvider).skipToNext(),
         ),
       ],
@@ -589,7 +590,7 @@ class _SecondaryControls extends StatelessWidget {
         IconButton(
           tooltip: shuffleOn ? 'Shuffle on' : 'Shuffle off',
           icon: Icon(
-            Icons.shuffle,
+            LucideIcons.shuffle,
             color: shuffleOn ? fs.accent : fs.ash,
           ),
           onPressed: actions.toggleShuffle,
@@ -602,8 +603,8 @@ class _SecondaryControls extends StatelessWidget {
           },
           icon: Icon(
             repeatMode == AudioServiceRepeatMode.one
-                ? Icons.repeat_one
-                : Icons.repeat,
+                ? LucideIcons.repeat_1
+                : LucideIcons.repeat,
             color: repeatMode == AudioServiceRepeatMode.none
                 ? fs.ash
                 : fs.accent,
@@ -612,7 +613,7 @@ class _SecondaryControls extends StatelessWidget {
         ),
         IconButton(
           tooltip: 'Queue',
-          icon: Icon(Icons.queue_music, color: fs.ash),
+          icon: Icon(LucideIcons.list_music, color: fs.ash),
           onPressed: () => GoRouter.of(context).push('/queue'),
         ),
         LikeButton(kind: LikeKind.track, id: media.id, size: 22),

flutter_client/lib/player/player_bar.dart

@@ -3,6 +3,7 @@ import 'dart:io';
 import 'package:audio_service/audio_service.dart';
 import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_lucide/flutter_lucide.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
@@ -229,7 +230,7 @@ class _PlayControls extends StatelessWidget {
           child: IconButton(
             padding: EdgeInsets.zero,
             iconSize: 22,
-            icon: Icon(Icons.skip_previous, color: fs.parchment),
+            icon: Icon(LucideIcons.skip_back, color: fs.parchment),
             onPressed: () => ref.read(audioHandlerProvider).skipToPrevious(),
           ),
         ),
@@ -240,7 +241,7 @@ class _PlayControls extends StatelessWidget {
             padding: EdgeInsets.zero,
             iconSize: 32,
             icon: Icon(
-              isPlaying ? Icons.pause_circle_filled : Icons.play_circle_filled,
+              isPlaying ? LucideIcons.circle_pause : LucideIcons.circle_play,
               color: fs.accent,
             ),
             onPressed: () {
@@ -259,7 +260,7 @@ class _PlayControls extends StatelessWidget {
           child: IconButton(
             padding: EdgeInsets.zero,
             iconSize: 22,
-            icon: Icon(Icons.skip_next, color: fs.parchment),
+            icon: Icon(LucideIcons.skip_forward, color: fs.parchment),
             onPressed: () => ref.read(audioHandlerProvider).skipToNext(),
           ),
         ),

flutter_client/lib/player/queue_screen.dart

@@ -1,5 +1,6 @@
 import 'package:audio_service/audio_service.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_lucide/flutter_lucide.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
@@ -20,7 +21,7 @@ class QueueScreen extends ConsumerWidget {
         backgroundColor: fs.obsidian,
         elevation: 0,
         leading: IconButton(
-          icon: Icon(Icons.arrow_back, color: fs.parchment),
+          icon: Icon(LucideIcons.arrow_left, color: fs.parchment),
           onPressed: () => context.pop(),
         ),
         title: Text('Queue', style: TextStyle(color: fs.parchment)),
@@ -84,7 +85,7 @@ class _QueueRow extends StatelessWidget {
           if (isCurrent)
             Padding(
               padding: const EdgeInsets.only(right: 8),
-              child: Icon(Icons.graphic_eq, color: fs.accent, size: 16),
+              child: Icon(LucideIcons.audio_lines, color: fs.accent, size: 16),
             ),
           Expanded(
             child: Column(