fix(ai): preserve custom model IDs across refresh

Fluid.xcodeproj/project.pbxproj

@@ -13,6 +13,7 @@
 		7C5AF14C2F15041600DE21B0 /* MediaRemoteAdapter in Embed Frameworks */ = {isa = PBXBuildFile; productRef = 7C5AF14A2F15041600DE21B0 /* MediaRemoteAdapter */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		7C9A71022F58B00000FB7CAF /* TranscribeCpp in Frameworks */ = {isa = PBXBuildFile; productRef = 7C9A71012F58B00000FB7CAF /* TranscribeCpp */; };
 		7C91B0012F42AA0100C0DEF0 /* HotkeyShortcutTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7C91B0022F42AA0100C0DEF0 /* HotkeyShortcutTests.swift */; };
+		A60100000000000000000002 /* AIModelRefreshTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = A60100000000000000000001 /* AIModelRefreshTests.swift */; };
 		7CDB0A2D2F3C4D5600FB7CAD /* DictationE2ETests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7CDB0A292F3C4D5600FB7CAD /* DictationE2ETests.swift */; };
 		7CDB0A2E2F3C4D5600FB7CAD /* AudioFixtureLoader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 7CDB0A2A2F3C4D5600FB7CAD /* AudioFixtureLoader.swift */; };
 		86CAA2D4EF18433096185602 /* LLMClientRequestBodyTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 343B29013F4441D6A797D12D /* LLMClientRequestBodyTests.swift */; };
@@ -49,6 +50,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		A60100000000000000000001 /* AIModelRefreshTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AIModelRefreshTests.swift; sourceTree = "<group>"; };
 		343B29013F4441D6A797D12D /* LLMClientRequestBodyTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LLMClientRequestBodyTests.swift; sourceTree = "<group>"; };
 		980330F3CE464336ADCE3E23 /* TemperatureSupportTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TemperatureSupportTests.swift; sourceTree = "<group>"; };
 		A62300000000000000000001 /* AudioBufferConverterTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AudioBufferConverterTests.swift; sourceTree = "<group>"; };
@@ -124,6 +126,7 @@
 			children = (
 				7CDB0A262F3C4D5600FB7CAD /* Helpers */,
 				7CDB0A272F3C4D5600FB7CAD /* Resources */,
+				A60100000000000000000001 /* AIModelRefreshTests.swift */,
 				7CDB0A292F3C4D5600FB7CAD /* DictationE2ETests.swift */,
 				7C91B0022F42AA0100C0DEF0 /* HotkeyShortcutTests.swift */,
 				343B29013F4441D6A797D12D /* LLMClientRequestBodyTests.swift */,
@@ -281,6 +284,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				A60100000000000000000002 /* AIModelRefreshTests.swift in Sources */,
 				7CDB0A2E2F3C4D5600FB7CAD /* AudioFixtureLoader.swift in Sources */,
 				7CDB0A2D2F3C4D5600FB7CAD /* DictationE2ETests.swift in Sources */,
 				7C91B0012F42AA0100C0DEF0 /* HotkeyShortcutTests.swift in Sources */,

Sources/Fluid/Persistence/BackupService.swift

@@ -10,6 +10,9 @@ struct BackupFileVersion: Codable, Equatable {
 struct SettingsBackupPayload: Codable, Equatable {
     let selectedProviderID: String
     let selectedModelByProvider: [String: String]
+    // Optional so backups created before custom model persistence still decode.
+    // swiftlint:disable:next discouraged_optional_collection
+    let customModelsByProvider: [String: [String]]?
     let savedProviders: [SettingsStore.SavedProvider]
     let modelReasoningConfigs: [String: SettingsStore.ModelReasoningConfig]
     let privateAIPrefixKVCacheEnabled: Bool?

Sources/Fluid/Persistence/SettingsStore.swift

@@ -22,6 +22,8 @@ final class SettingsStore: ObservableObject {
     static let privateAIDictationMinimumOutputTokens = 256
     static let privateAIDictationRoundTripTokenCost = 2.75
     static let privateAIBackendPreferenceDefaultsKey = "FluidIntelligenceBackendPreference"
+    static let customModelsByProviderDefaultsKey = "CustomModelsByProvider"
+    static let legacyModelCandidatesDefaultsKey = "LegacyModelCandidatesByProvider"
     private static let forcedOnboardingResetIntroducedAt = Date(timeIntervalSince1970: 1_782_091_732)
     private let defaults = UserDefaults.standard
     private let keychain = KeychainService.shared
@@ -1412,6 +1414,127 @@ final class SettingsStore: ObservableObject {
         }
     }
 
+    var customModelsByProvider: [String: [String]] {
+        get {
+            (self.defaults.dictionary(forKey: Self.customModelsByProviderDefaultsKey) as? [String: [String]]) ?? [:]
+        }
+        set {
+            objectWillChange.send()
+            self.defaults.set(newValue, forKey: Self.customModelsByProviderDefaultsKey)
+        }
+    }
+
+    var hasStoredCustomModelsByProvider: Bool {
+        self.defaults.object(forKey: Self.customModelsByProviderDefaultsKey) != nil
+    }
+
+    func clearStoredCustomModelsByProvider() {
+        objectWillChange.send()
+        self.defaults.removeObject(forKey: Self.customModelsByProviderDefaultsKey)
+    }
+
+    var legacyModelCandidatesByProvider: [String: [String]] {
+        get {
+            (self.defaults.dictionary(
+                forKey: Self.legacyModelCandidatesDefaultsKey
+            ) as? [String: [String]]) ?? [:]
+        }
+        set {
+            objectWillChange.send()
+            self.defaults.set(newValue, forKey: Self.legacyModelCandidatesDefaultsKey)
+        }
+    }
+
+    func clearStoredLegacyModelCandidatesByProvider() {
+        objectWillChange.send()
+        self.defaults.removeObject(forKey: Self.legacyModelCandidatesDefaultsKey)
+    }
+
+    static func availableModelsAfterRestore(
+        customModelsByProvider: [String: [String]],
+        savedProviders: [SavedProvider]
+    ) -> [String: [String]] {
+        func normalized(_ models: [String]) -> [String] {
+            var seen: Set<String> = []
+            return models.compactMap { model in
+                let trimmed = model.trimmingCharacters(in: .whitespacesAndNewlines)
+                guard !trimmed.isEmpty, seen.insert(trimmed).inserted else { return nil }
+                return trimmed
+            }
+        }
+
+        func providerKey(_ providerID: String) -> String {
+            let trimmed = providerID.trimmingCharacters(in: .whitespacesAndNewlines)
+            guard !trimmed.isEmpty else { return "" }
+            let lower = trimmed.lowercased()
+            if ModelRepository.shared.isBuiltIn(lower) {
+                return lower
+            }
+            return trimmed.hasPrefix("custom:") ? trimmed : "custom:\(trimmed)"
+        }
+
+        var restored: [String: [String]] = [:]
+        for provider in savedProviders {
+            let key = providerKey(provider.id)
+            let models = normalized(provider.models)
+            if !key.isEmpty, !models.isEmpty {
+                restored[key] = models
+            }
+        }
+
+        for (providerID, customModels) in customModelsByProvider {
+            let key = providerKey(providerID)
+            guard !key.isEmpty else { continue }
+            let defaults = ModelRepository.shared.isBuiltIn(key)
+                ? ModelRepository.shared.defaultModels(for: key)
+                : restored[key] ?? []
+            let models = normalized(defaults + customModels)
+            if models.isEmpty {
+                restored.removeValue(forKey: key)
+            } else {
+                restored[key] = models
+            }
+        }
+        return restored
+    }
+
+    func restoreModelCatalogState(
+        customModelsByProvider: [String: [String]],
+        savedProviders: [SavedProvider]
+    ) {
+        self.availableModels = []
+        self.clearStoredLegacyModelCandidatesByProvider()
+        self.customModelsByProvider = customModelsByProvider
+        self.availableModelsByProvider = Self.availableModelsAfterRestore(
+            customModelsByProvider: customModelsByProvider,
+            savedProviders: savedProviders
+        )
+    }
+
+    func prepareLegacyModelCatalogRestore(savedProviders: [SavedProvider]) {
+        self.availableModels = []
+        self.availableModelsByProvider = Self.availableModelsAfterRestore(
+            customModelsByProvider: [:],
+            savedProviders: savedProviders
+        )
+        self.clearStoredCustomModelsByProvider()
+        self.clearStoredLegacyModelCandidatesByProvider()
+    }
+
+    func customModelsByProviderForBackup() -> [String: [String]] {
+        guard !self.hasStoredCustomModelsByProvider else {
+            return self.customModelsByProvider
+        }
+        let savedModelsByProvider = Dictionary(
+            self.savedProviders.map { ($0.id, $0.models) },
+            uniquingKeysWith: { _, newer in newer }
+        )
+        return AIModelCatalog.migratedLegacyCustomModels(
+            cachedModelsByProvider: self.availableModelsByProvider,
+            savedModelsByProvider: savedModelsByProvider
+        )
+    }
+
     var enableDebugLogs: Bool {
         get {
             let value = self.defaults.object(forKey: Keys.enableDebugLogs)
@@ -2994,6 +3117,7 @@ final class SettingsStore: ObservableObject {
         SettingsBackupPayload(
             selectedProviderID: self.selectedProviderID,
             selectedModelByProvider: self.selectedModelByProvider,
+            customModelsByProvider: self.customModelsByProviderForBackup(),
             savedProviders: self.savedProviders,
             modelReasoningConfigs: self.modelReasoningConfigs,
             privateAIPrefixKVCacheEnabled: self.privateAIPrefixKVCacheEnabled,
@@ -3095,6 +3219,14 @@ final class SettingsStore: ObservableObject {
         self.savedProviders = payload.savedProviders
         self.selectedProviderID = payload.selectedProviderID
         self.selectedModelByProvider = payload.selectedModelByProvider
+        if let customModelsByProvider = payload.customModelsByProvider {
+            self.restoreModelCatalogState(
+                customModelsByProvider: customModelsByProvider,
+                savedProviders: self.savedProviders
+            )
+        } else {
+            self.prepareLegacyModelCatalogRestore(savedProviders: self.savedProviders)
+        }
         self.modelReasoningConfigs = payload.modelReasoningConfigs
         if let privateAIPrefixKVCacheEnabled = payload.privateAIPrefixKVCacheEnabled {
             self.privateAIPrefixKVCacheEnabled = privateAIPrefixKVCacheEnabled