feat(drive): user can rename drive

- only owners can rename root folders name (aka the drive name)
    - add UI to rename drive's name

frontend/src/routes/config/drive/[uuid]/+page.svelte

@@ -4,6 +4,8 @@
 	import { onMount } from 'svelte';
 
 	import { listDriveMembers } from '$lib/api/endpoints/drives';
+	import { renameFolder } from '$lib/api/endpoints/folders';
+	import { errorToast } from '$lib/utils/errors';
 	import type { Drive, DriveMember, DriveRole } from '$lib/api/types';
 	import ShareDialog from '$lib/components/ShareDialog.svelte';
 	import UserVignette from '$lib/components/UserVignette.svelte';
@@ -26,6 +28,55 @@
 	// honest UX. Shared drives + Owner role → full controls.
 	const canManageMembers = $derived(drive?.kind === 'shared' && drive?.caller_role === 'owner');
 
+	// Rename is allowed for any Owner (both shared and personal), since
+	// the backend requires `Permission::Manage` on the drive's root
+	// folder which only the Owner bundle carries. Personal-drive Owners
+	// are the user themselves (seeded by the lifecycle hook).
+	const canRename = $derived(drive?.caller_role === 'owner');
+
+	// Inline rename state. `renameDraft` shadows `drive.name` while the
+	// input is open; we don't write back to the store until the server
+	// accepts the change. `renameBusy` disables the save/cancel buttons
+	// during the round-trip.
+	let renaming = $state(false);
+	let renameDraft = $state('');
+	let renameBusy = $state(false);
+
+	function startRename() {
+		if (!drive) return;
+		renameDraft = drive.name;
+		renaming = true;
+	}
+
+	function cancelRename() {
+		renaming = false;
+		renameDraft = '';
+	}
+
+	async function saveRename() {
+		if (!drive) return;
+		const next = renameDraft.trim();
+		if (next.length === 0 || next === drive.name) {
+			cancelRename();
+			return;
+		}
+		renameBusy = true;
+		try {
+			// Drive name = root folder name (drive.md §3); rename via the
+			// folder endpoint. Backend promotes the perm to Manage for
+			// parent_id IS NULL, so a non-Owner caller would 404 here
+			// (but the UI also hid this button for non-Owners).
+			await renameFolder(drive.root_folder_id, next);
+			drivesStore.invalidate();
+			await drivesStore.load();
+			renaming = false;
+		} catch (e) {
+			errorToast(e);
+		} finally {
+			renameBusy = false;
+		}
+	}
+
 	function roleLabel(role: DriveRole): string {
 		switch (role) {
 			case 'owner':
@@ -153,10 +204,59 @@
 			<a class="link" href={resolve('/files')}>{t('drive.back_to_files', 'Back to Files')}</a>
 		</div>
 	{:else}
-		<h1>
+		<div class="drive-title">
 			<Icon name={driveIcon(drive)} />
-			{drive.name}
+			{#if renaming}
-		</h1>
+				<input
+					class="drive-title__input"
+					type="text"
+					data-testid="drive-rename-input"
+					bind:value={renameDraft}
+					maxlength="200"
+					disabled={renameBusy}
+					onkeydown={(e) => {
+						if (e.key === 'Enter') void saveRename();
+						else if (e.key === 'Escape') cancelRename();
+					}}
+				/>
+				<button
+					type="button"
+					class="icon-btn"
+					data-testid="drive-rename-save-btn"
+					title={t('common.save', 'Save')}
+					aria-label={t('common.save', 'Save')}
+					onclick={() => void saveRename()}
+					disabled={renameBusy}
+				>
+					<Icon name="check" />
+				</button>
+				<button
+					type="button"
+					class="icon-btn"
+					data-testid="drive-rename-cancel-btn"
+					title={t('common.cancel', 'Cancel')}
+					aria-label={t('common.cancel', 'Cancel')}
+					onclick={cancelRename}
+					disabled={renameBusy}
+				>
+					<Icon name="times" />
+				</button>
+			{:else}
+				<h1 class="drive-title__name">{drive.name}</h1>
+				{#if canRename}
+					<button
+						type="button"
+						class="icon-btn"
+						data-testid="drive-rename-edit-btn"
+						title={t('drive.rename', 'Rename drive')}
+						aria-label={t('drive.rename', 'Rename drive')}
+						onclick={startRename}
+					>
+						<Icon name="pencil-alt" />
+					</button>
+				{/if}
+			{/if}
+		</div>
 
 		<div class="card">
 			<h2><Icon name="info-circle" /> {t('drive.info', 'Drive info')}</h2>
@@ -402,6 +502,54 @@
 		text-decoration: underline;
 	}
 
+	/* Drive title row: icon + name (or inline rename input) + edit/save
+	   affordances. Mirrors the visual weight of the previous static
+	   <h1> so the page layout doesn't shift when entering rename mode. */
+	.drive-title {
+		display: flex;
+		align-items: center;
+		gap: 0.5rem;
+		margin-bottom: 1rem;
+	}
+
+	.drive-title__name {
+		margin: 0;
+	}
+
+	.drive-title__input {
+		flex: 1;
+		min-width: 0;
+		max-width: 28rem;
+		padding: 0.4rem 0.6rem;
+		font-size: 1.5rem;
+		font-weight: var(--weight-semibold, 600);
+		border: 1px solid var(--color-border);
+		border-radius: var(--radius-md);
+		background: var(--color-bg-input);
+		color: var(--color-text);
+	}
+
+	/* Compact icon button used in the title row + nowhere else here.
+	   The shared `.icon-btn` style isn't promoted to a global yet, so
+	   we duplicate the minimum that this page needs. */
+	.icon-btn {
+		display: inline-flex;
+		align-items: center;
+		justify-content: center;
+		width: 2rem;
+		height: 2rem;
+		border: 1px solid var(--color-border);
+		border-radius: var(--radius-md);
+		background: var(--color-bg-surface);
+		color: var(--color-text);
+		cursor: pointer;
+	}
+
+	.icon-btn:disabled {
+		opacity: 0.45;
+		cursor: not-allowed;
+	}
+
 	/* Members card header: title on the left, "Manage members" button on
 	   the right when the caller can mutate membership. */
 	.members__header {

src/application/services/folder_service.rs

@@ -446,10 +446,32 @@ impl FolderUseCase for FolderService {
             )));
         }
 
+        // Drive roots double as the drive's display name (per drive.md §3,
+        // `drives.name` is sourced from `storage.folders.name` of the row
+        // pointed at by `root_folder_id`). Per drive.md §6 the rename is
+        // Owner-only — but with `Permission::Update` that's leaky because
+        // every Editor of the drive has Update on every folder in the
+        // drive, including the root. So we promote the requirement to
+        // `Manage` for root folders. A root is identified by
+        // `parent_id IS NULL`; that's the same property the drive seeder
+        // and the drive-of-resource resolver rely on, so no schema-level
+        // assumption shifts here.
+        let folder = self.folder_storage.get_folder(id).await.map_err(|e| {
+            DomainError::internal_error(
+                "FolderStorage",
+                format!("Failed to look up folder before rename: {id}: {e}"),
+            )
+        })?;
+        let required_perm = if folder.parent_id().is_none() {
+            Permission::Manage
+        } else {
+            Permission::Update
+        };
+
         self.authz
             .require(
                 Subject::User(caller_id),
-                Permission::Update,
+                required_perm,
                 Self::folder_resource(id)?,
             )
             .await?;

tests/api/drives_membership.hurl

@@ -704,30 +704,19 @@ HTTP 404
 
 
 # 26d — Editor renames the drive (root folder) → 404.
-#       Editor bundle has Update on content, but the rename
+#       Folder rename normally requires `Permission::Update` (which
-#       endpoint uses authz.require(...) and Editor's bundle on
+#       Editor has on every folder in the drive via the engine's drive
-#       the drive root resolves through the same drive precheck.
+#       precheck). The folder service promotes the requirement to
-#       Editor has Update; folder rename uses Update; so this
+#       `Permission::Manage` when the target folder has `parent_id IS
-#       should actually SUCCEED. Asserting 200 to reflect the
+#       NULL` — i.e. it's a drive root — so the drive-rename surface is
-#       real engine semantics — the "Editor can rename the drive"
+#       Owner-only per drive.md §6, without changing the public folder
-#       fact is a real product question worth surfacing here.
+#       endpoint shape. Anti-enum: refusal returns 404 (not 403).
-#       If you want rename to be Owner-only, the fix is in the
-#       folder service (require Manage, not Update).
 PUT {{base_url}}/api/folders/{{team_root_folder_id}}/rename
 Authorization: Bearer {{bob_token}}
 Content-Type: application/json
 { "name": "team-drive-editor-renamed" }
 
-HTTP 200
+HTTP 404
-
-
-# Restore the previous name so downstream assertions don't drift.
-PUT {{base_url}}/api/folders/{{team_root_folder_id}}/rename
-Authorization: Bearer {{alice_token}}
-Content-Type: application/json
-{ "name": "team-drive-renamed" }
-
-HTTP 200
 
 
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