feat(documents): rename a document folder in place

InterlinedList.xcodeproj/project.pbxproj

@@ -73,6 +73,7 @@
 		A057072E1611947A2415D4D9 /* DocumentCollaboratorsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5110757D7694EC9FBF4366F7 /* DocumentCollaboratorsView.swift */; };
 		A1B1C1D1E1F10001 /* InterlinedListApp.swift in Sources */ = {isa = PBXBuildFile; fileRef = A1B1C1D1E1F10002 /* InterlinedListApp.swift */; };
 		A1B1C1D1E1F10003 /* RootView.swift in Sources */ = {isa = PBXBuildFile; fileRef = A1B1C1D1E1F10004 /* RootView.swift */; };
+		90B9BB00F26A98E19FEAE318 /* APIClient+Documents.swift in Sources */ = {isa = PBXBuildFile; fileRef = 1F84433332486544DA15C7BA /* APIClient+Documents.swift */; };
 		A1B1C1D1E1F10005 /* User.swift in Sources */ = {isa = PBXBuildFile; fileRef = A1B1C1D1E1F10006 /* User.swift */; };
 		A1B1C1D1E1F10007 /* Message.swift in Sources */ = {isa = PBXBuildFile; fileRef = A1B1C1D1E1F10008 /* Message.swift */; };
 		A1B1C1D1E1F10009 /* KeychainService.swift in Sources */ = {isa = PBXBuildFile; fileRef = A1B1C1D1E1F1000A /* KeychainService.swift */; };
@@ -287,6 +288,7 @@
 		8E384ED04860E87973898F89 /* DocumentSyncMergeTests.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = DocumentSyncMergeTests.swift; sourceTree = "<group>"; };
 		907AC4BA9A6A5DF132AEF075 /* APIClientLinkMetadataTests.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = APIClientLinkMetadataTests.swift; sourceTree = "<group>"; };
 		90E55EFCB42C25CBC10B3942 /* DMThreadView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DMThreadView.swift; sourceTree = "<group>"; };
+		1F84433332486544DA15C7BA /* APIClient+Documents.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = "APIClient+Documents.swift"; sourceTree = "<group>"; };
 		93642F79C3049C4A2ECC8AFF /* GapModelsTests.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = GapModelsTests.swift; sourceTree = "<group>"; };
 		93B62D89758287A728A56C9B /* APIClientSearchUsersTests.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = APIClientSearchUsersTests.swift; sourceTree = "<group>"; };
 		956BD8A48B0F2C66C2C6362A /* AppDeepLinkParseTests.swift */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = sourcecode.swift; path = AppDeepLinkParseTests.swift; sourceTree = "<group>"; };
@@ -534,6 +536,7 @@
 				B1C1D1E1F1A10002 /* DataCache.swift */,
 				B1C1D1E1F1A10004 /* AppDataStore.swift */,
 				D0A1D0A1D0A10002 /* OAuthCoordinator.swift */,
+				1F84433332486544DA15C7BA /* APIClient+Documents.swift */,
 				FC5914D730B4355F02E89D81 /* ILColor.swift */,
 				8B79D26B822DCA1188DF37E9 /* PushService.swift */,
 				5A04FF25F89FC0E5253896FD /* ImageUploadProcessor.swift */,
@@ -870,6 +873,7 @@
 				B1C1D1E1F1A1000D /* ListItemFormView.swift in Sources */,
 				D0A1D0A1D0A10001 /* OAuthCoordinator.swift in Sources */,
 				D0A1D0A1D0A10003 /* ChangeEmailView.swift in Sources */,
+				90B9BB00F26A98E19FEAE318 /* APIClient+Documents.swift in Sources */,
 				D0A1D0A1D0A10005 /* ForgotPasswordView.swift in Sources */,
 				D0A1D0A1D0A10007 /* ResetPasswordView.swift in Sources */,
 				D0A1D0A1D0A10009 /* EmailVerificationBanner.swift in Sources */,

InterlinedList/Models/Document.swift

@@ -55,6 +55,14 @@ struct DocumentFolder: Codable, Identifiable {
     }
 }
 
+extension DocumentFolder {
+    /// A copy under a new name, for showing a rename before the server confirms it.
+    func renamed(to newName: String) -> DocumentFolder {
+        DocumentFolder(id: id, name: newName, parentId: parentId,
+                       updatedAt: updatedAt, deletedAt: deletedAt)
+    }
+}
+
 /// A starter document a subscriber can copy into a new document. `id` is the
 /// source document's id (`templateDocumentId` for `POST /api/documents/from-template`).
 struct DocumentTemplate: Codable, Identifiable {

InterlinedList/Services/APIClient+Documents.swift

@@ -0,0 +1,62 @@
+import Foundation
+
+/// How a folder update should treat `parentId`.
+///
+/// `PUT /api/documents/folders/{id}` only validates and applies a move when the
+/// `parentId` key is *present* in the body, and Swift's synthesized `Encodable`
+/// drops a `nil` optional rather than writing `null`. Without this distinction a
+/// rename would be indistinguishable from a move to root.
+enum DocumentFolderParentUpdate: Equatable {
+    /// Leave the folder where it is — omit `parentId` entirely.
+    case unchanged
+    /// Move to the top level — send an explicit `null`.
+    case root
+    /// Move under another folder.
+    case folder(String)
+}
+
+extension APIClient {
+    /// Renames and/or moves a document folder (`PUT /api/documents/folders/{id}`).
+    ///
+    /// The route reads plain camelCase keys (`name`, `parentId`), so this goes
+    /// through `putCamel` — the snake_case `put` would send `parent_id`, which the
+    /// server ignores, silently dropping the move.
+    ///
+    /// A move that would make the folder its own ancestor is rejected server-side
+    /// with a `400` whose body carries readable text, which `checkResponse` surfaces
+    /// as `APIError.server(_:)`. A name that collides with a sibling comes back the
+    /// same way with a `409`.
+    func updateDocumentFolder(id: String,
+                              name: String? = nil,
+                              parentId: DocumentFolderParentUpdate = .unchanged) async throws -> DocumentFolder {
+        struct Response: Decodable { let folder: DocumentFolder? }
+        let encoded = id.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? id
+        let response: Response = try await putCamel(
+            "/api/documents/folders/\(encoded)",
+            body: UpdateDocumentFolderBody(name: name, parentId: parentId))
+        guard let folder = response.folder else { throw APIError.noData }
+        return folder
+    }
+}
+
+/// Encodes only the fields the caller actually wants changed, so a rename never
+/// re-sends (and re-validates) the folder's parent.
+private struct UpdateDocumentFolderBody: Encodable {
+    let name: String?
+    let parentId: DocumentFolderParentUpdate
+
+    private enum CodingKeys: String, CodingKey { case name, parentId }
+
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+        try container.encodeIfPresent(name, forKey: .name)
+        switch parentId {
+        case .unchanged:
+            break
+        case .root:
+            try container.encodeNil(forKey: .parentId)
+        case .folder(let id):
+            try container.encode(id, forKey: .parentId)
+        }
+    }
+}

InterlinedList/Services/AppDataStore.swift

@@ -506,6 +506,20 @@ final class AppDataStore: ObservableObject {
     }
     func removeDocumentFolder(id: String) { documentFolders.removeAll { $0.id == id }; persistDocs() }
 
+    /// Mirrors a renamed/moved folder into the local tree and persists it, so the
+    /// change survives a cold start the way a create or delete does.
+    ///
+    /// Unlike `createDocumentFolderOffline` / `deleteDocumentFolderOffline` this
+    /// deliberately enqueues **no** sync operation: `POST /api/documents/sync`
+    /// answers a folder update with `unsupported_operation` ("Folders support only
+    /// `create` and `delete`"), so the change reaches the server through
+    /// `PUT /api/documents/folders/{id}` and this only mirrors the result.
+    func updateDocumentFolder(_ folder: DocumentFolder) {
+        guard let idx = documentFolders.firstIndex(where: { $0.id == folder.id }) else { return }
+        documentFolders[idx] = folder
+        persistDocs()
+    }
+
     private func persistDocs() {
         if offlineDocSyncEnabled {
             saveDocsSyncCache()