refactor(api): co-locate server-protocol clients into lib/api

Move the Subsonic + Navidrome protocol clients and the library IPC facade
(subsonic*, navidrome*, library.ts + tests) from src/api/ into src/lib/api/,
the feature-free infra layer (plan M4, decision §10.3: shared client core → lib/).
Pure move: deep-path import specifiers @/api/* -> @/lib/api/* across ~150
consumers; no behaviour change. Domain REST (lyrics/events) and cover/analysis
infra stay in src/api/ pending their own M4 placement.

tsc 0, lint 0/0, full suite 319 files / 2353 tests green.

src/features/settings/components/AnalyticsStrategySection.tsx

@@ -19,8 +19,8 @@ import {
   libraryAnalysisProgress,
   type LibraryAnalysisProgressDto,
 } from '@/api/analysis';
-import { libraryGetTracksBatch, type LibraryTrackDto, type TrackRefDto } from '@/api/library';
-import { buildStreamUrlForServer } from '@/api/subsonicStreamUrl';
+import { libraryGetTracksBatch, type LibraryTrackDto, type TrackRefDto } from '@/lib/api/library';
+import { buildStreamUrlForServer } from '@/lib/api/subsonicStreamUrl';
 import { serverListDisplayLabel } from '@/utils/server/serverDisplayName';
 import { serverIndexKeyForProfile } from '@/utils/server/serverIndexKey';
 import { showToast } from '@/utils/ui/toast';

src/features/settings/components/ServerLibraryIndexControls.tsx

@@ -1,6 +1,6 @@
 import { RefreshCw, ShieldCheck, WifiOff, Zap } from 'lucide-react';
 import { useTranslation } from 'react-i18next';
-import type { SyncStateDto } from '@/api/library';
+import type { SyncStateDto } from '@/lib/api/library';
 import {
   libraryStatusDisplayTrackCount,
   libraryStatusIsReady,

src/features/settings/components/ServersTab.tsx

@@ -7,12 +7,12 @@ import { useAuthStore } from '@/store/authStore';
 import { formatServerSoftware, isNavidromeAudiomuseSoftwareEligible, type InstantMixProbeResult, type SubsonicServerIdentity } from '@/utils/server/subsonicServerIdentity';
 import { buildCapabilityContext } from '@/serverCapabilities/context';
 import { useLibraryIndexStore } from '@/store/libraryIndexStore';
-import { libraryDeleteServerData, librarySyncClearSession } from '@/api/library';
+import { libraryDeleteServerData, librarySyncClearSession } from '@/lib/api/library';
 import { bootstrapIndexedServer } from '@/utils/library/librarySession';
 import { useLibraryIndexSync } from '@/hooks/useLibraryIndexSync';
 import ServerLibraryIndexControls from '@/features/settings/components/ServerLibraryIndexControls';
 import type { ServerProfile } from '@/store/authStoreTypes';
-import { pingWithCredentialsForProfile, scheduleInstantMixProbeForServer } from '@/api/subsonic';
+import { pingWithCredentialsForProfile, scheduleInstantMixProbeForServer } from '@/lib/api/subsonic';
 import {
   clearServerHttpContext,
   syncServerHttpContextForProfile,

src/features/settings/components/UserForm.tsx

@@ -1,7 +1,7 @@
 import React, { useEffect, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { Shield, Wand2 } from 'lucide-react';
-import { ndUpdateUser, type NdLibrary, type NdUser } from '@/api/navidromeAdmin';
+import { ndUpdateUser, type NdLibrary, type NdUser } from '@/lib/api/navidromeAdmin';
 import { showToast } from '@/utils/ui/toast';
 import {
   copyTextToClipboard,

src/features/settings/components/UserManagementSection.tsx

@@ -1,7 +1,7 @@
 import { useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { RotateCcw, UserPlus, Users } from 'lucide-react';
-import type { NdUser } from '@/api/navidromeAdmin';
+import type { NdUser } from '@/lib/api/navidromeAdmin';
 import ConfirmModal from '@/components/ConfirmModal';
 import { useUserMgmtData } from '@/features/settings/hooks/useUserMgmtData';
 import { useUserMgmtActions } from '@/features/settings/hooks/useUserMgmtActions';

src/features/settings/components/userMgmt/MagicStringModal.tsx

@@ -2,7 +2,7 @@ import React, { useState } from 'react';
 import { createPortal } from 'react-dom';
 import { X } from 'lucide-react';
 import type { TFunction } from 'i18next';
-import { ndUpdateUser, type NdUser } from '@/api/navidromeAdmin';
+import { ndUpdateUser, type NdUser } from '@/lib/api/navidromeAdmin';
 import { showToast } from '@/utils/ui/toast';
 import {
   copyTextToClipboard,

src/features/settings/components/userMgmt/UserMgmtRow.tsx

@@ -1,7 +1,7 @@
 import React from 'react';
 import { Shield, Trash2, User, Wand2 } from 'lucide-react';
 import type { i18n as I18nType, TFunction } from 'i18next';
-import type { NdLibrary, NdUser } from '@/api/navidromeAdmin';
+import type { NdLibrary, NdUser } from '@/lib/api/navidromeAdmin';
 import { formatLastSeen } from '@/utils/componentHelpers/userMgmtHelpers';
 
 interface Props {

src/features/settings/hooks/useUserMgmtActions.ts

@@ -7,7 +7,7 @@ import {
   ndUpdateUser,
   type NdLibrary,
   type NdUser,
-} from '@/api/navidromeAdmin';
+} from '@/lib/api/navidromeAdmin';
 import { showToast } from '@/utils/ui/toast';
 import {
   copyTextToClipboard,

src/features/settings/hooks/useUserMgmtData.ts

@@ -5,7 +5,7 @@ import {
   ndListUsers,
   type NdLibrary,
   type NdUser,
-} from '@/api/navidromeAdmin';
+} from '@/lib/api/navidromeAdmin';
 
 interface UseUserMgmtDataResult {
   users: NdUser[];

src/features/settings/pages/Settings.tsx

@@ -20,7 +20,7 @@ import { SystemTab } from '@/features/settings/components/SystemTab';
 import { searchSettings, type SettingsSearchHit } from '@/features/settings/components/settingsSearch';
 import { type Tab, resolveTab } from '@/features/settings/components/settingsTabs';
 import { UserManagementSection } from '@/features/settings/components/UserManagementSection';
-import { ndLogin } from '@/api/navidromeAdmin';
+import { ndLogin } from '@/lib/api/navidromeAdmin';
 import { type ServerMagicPayload } from '@/utils/server/serverMagicString';