feat(ui): folder picker sort/filter/create/rename and exclusions size rollups

Closes #305, #306, #307.

- Destination folder picker: client-side sort (name/modified, Shared Drive
  roots pinned first), type-to-filter (auto-focus, resets on navigation),
  inline "New folder" on every browsable backend, inline hover-rename on
  Drive + SFTP (disabled with an explanatory tooltip on S3), row-level
  inline errors, near-fullscreen sizing in the add-source wizard modal.
- Exclusions preview tree: per-folder file-count + byte-size rollups
  streamed from the backend walker (settle progressively for a descended
  folder, final immediately for a pruned excluded folder via a lightweight
  recursive disk count), an excluded-bytes "would be freed" summary stat,
  and the same near-fullscreen sizing.
- New RemoteStore::rename_folder (Drive PATCH, SFTP real rename + sidecar
  move, S3 stays unsupported by design) and create_remote_folder/
  rename_remote_folder IPC commands; BackendDto.supportsRename and
  DriveFolderEntry.modifiedTime added to the wire contract.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019xKUm9vH4ifb5LHR5szy1v

Author: pmaxhogan

README.md

@@ -122,7 +122,9 @@ These move: check each project's current docs before relying on a cell.
   exclude rules, and a configurable symlink policy, and that skips excluded
   directories instead of descending them.
 - Live exclusion preview that re-classifies the folder tree as you edit a rule,
-  from an in-memory tree rather than a fresh walk of the disk.
+  from an in-memory tree rather than a fresh walk of the disk, with a
+  per-folder file-count and size rollup so an exclude rule's actual weight -
+  or what re-including it would cost - is visible before you commit to it.
 - Exclusion rules that take effect immediately, even mid-backup: saving a new
   rule stops the running backup from uploading anything it newly excludes at the
   next file boundary (the file already in flight still finishes cleanly), and
@@ -192,6 +194,11 @@ These move: check each project's current docs before relying on a cell.
   plain local / removable folder (USB drive, external disk, NAS share) - all
   behind one pluggable backend trait, so adding the next one is a new backend
   crate plus a factory arm rather than a fork of every call site.
+- Destination folder picker with client-side sort (name or last-modified) and
+  type-to-filter, a "New folder" button on every browsable destination, and
+  inline rename on Google Drive and SFTP (S3's key-prefix "folders" have no
+  separate identity to rename, so that control is disabled there with an
+  explanation instead of hidden outright).
 - Scheduled integrity scrub: on top of the local re-hash and the
   remote-existence audit above, a rolling background pass re-checks each
   already-backed-up object's size, and its content checksum where the

crates/driven-backend/src/lib.rs

@@ -128,6 +128,9 @@ pub struct BackendDescriptor {
     /// file, so a point-in-time restore returns the older bytes rather than
     /// today's (`BackendKind::supports_version_history`; issue #220).
     pub supports_version_history: bool,
+    /// Whether the destination picker's inline rename affordance applies to
+    /// this backend's folder rows (`BackendKind::supports_rename`; issue #307).
+    pub supports_rename: bool,
 }
 
 /// Every destination this build can construct, in picker order. The first entry
@@ -142,6 +145,7 @@ pub fn descriptors() -> Vec<BackendDescriptor> {
             uses_oauth: kind.uses_oauth(),
             supports_folder_picker: kind.supports_folder_picker(),
             supports_version_history: kind.supports_version_history(),
+            supports_rename: kind.supports_rename(),
         })
         .collect()
 }
@@ -551,6 +555,7 @@ mod tests {
                 desc.supports_version_history,
                 kind.supports_version_history()
             );
+            assert_eq!(desc.supports_rename, kind.supports_rename());
         }
         assert_eq!(d[0].kind, BackendKind::default());
     }

crates/driven-core/src/types.rs

@@ -1253,6 +1253,13 @@ pub enum ErrorCode {
     /// (the identity marker, then the write/remove round trip), since the
     /// remedy is identical either way.
     SftpRootNotWritable,
+    /// `remote.rename_unsupported` - the destination picker's inline rename
+    /// (issue #307) was called against a backend whose `RemoteStore` has no
+    /// rename primitive (S3, whose "folders" are key prefixes with no
+    /// separate identity to rename). The picker UI hides the affordance for
+    /// such backends already (`BackendKind::supports_rename`); reaching this
+    /// code means a stale client called it anyway.
+    RemoteRenameUnsupported,
 }
 
 impl ErrorCode {
@@ -1311,6 +1318,7 @@ impl ErrorCode {
             ErrorCode::SftpRootNotADirectory => "sftp.root_not_a_directory",
             ErrorCode::SftpDestMarkerMismatch => "sftp.dest_marker_mismatch",
             ErrorCode::SftpRootNotWritable => "sftp.root_not_writable",
+            ErrorCode::RemoteRenameUnsupported => "remote.rename_unsupported",
         }
     }
 
@@ -1373,6 +1381,7 @@ impl ErrorCode {
             "sftp.root_not_a_directory" => ErrorCode::SftpRootNotADirectory,
             "sftp.dest_marker_mismatch" => ErrorCode::SftpDestMarkerMismatch,
             "sftp.root_not_writable" => ErrorCode::SftpRootNotWritable,
+            "remote.rename_unsupported" => ErrorCode::RemoteRenameUnsupported,
             _ => return None,
         })
     }

crates/driven-drive/src/fake/mod.rs

@@ -1110,6 +1110,34 @@ impl RemoteStore for InMemoryRemoteStore {
             .collect())
     }
 
+    /// Renames a folder in place, mirroring `GoogleDriveStore::rename_folder`
+    /// (issue #307): only `name` changes, id and `parent_id` are untouched.
+    async fn rename_folder(
+        &self,
+        folder_id: &str,
+        new_name: &str,
+        drive_context: &DriveContext,
+    ) -> anyhow::Result<RemoteEntry> {
+        self.record_context(drive_context);
+        self.check_request_faults(RequestKind::WriteTarget).await?;
+        let mut guard = self.inner.lock();
+        if !guard
+            .objects
+            .get(folder_id)
+            .is_some_and(FileEntry::is_folder)
+        {
+            anyhow::bail!("fake: no folder with file_id {folder_id}");
+        }
+        let new_now = guard.tick();
+        let entry = guard
+            .objects
+            .get_mut(folder_id)
+            .expect("presence just checked above");
+        entry.name = new_name.to_string();
+        entry.modified_time_ms = new_now;
+        Ok(entry.to_remote_entry())
+    }
+
     async fn create(
         &self,
         parent_id: &str,

crates/driven-drive/src/google/mod.rs

@@ -1108,6 +1108,33 @@ impl RemoteStore for GoogleDriveStore {
         self.list_query(&q, drive_context).await
     }
 
+    /// Renames a folder via `PATCH /files/{id}` with just the `name` field -
+    /// the id and `parents` are untouched (issue #307). Unlike `create_folder`
+    /// this is a PATCH-by-id, which is idempotent, so it is safe to blind-retry
+    /// through the normal `send_json` path.
+    async fn rename_folder(
+        &self,
+        folder_id: &str,
+        new_name: &str,
+        _drive_context: &DriveContext,
+    ) -> anyhow::Result<RemoteEntry> {
+        let body = json_body(&serde_json::json!({ "name": new_name }))?;
+        let file: DriveFile = self
+            .send_json(|token| {
+                self.http
+                    .patch(format!("{DRIVE_API_BASE}/files/{folder_id}"))
+                    .query(&[("fields", pagination::FILE_FIELDS), SUPPORTS_ALL_DRIVES])
+                    .bearer_auth(token)
+                    .header(reqwest::header::CONTENT_TYPE, "application/json")
+                    .body(body.clone())
+            })
+            .await
+            // The target is `folder_id`; a 404 / unclassified 403 is a
+            // dest-folder condition, not a transient (mirrors `create_folder`).
+            .map_err(map_parent_write_error)?;
+        Ok(file.into_remote_entry())
+    }
+
     async fn create(
         &self,
         parent_id: &str,

crates/driven-drive/tests/fake_contract.rs

@@ -1004,3 +1004,69 @@ async fn fake_with_fileid_recycle_reuses_trashed_id() {
         "exactly one live object now holds the recycled id"
     );
 }
+
+// ---------------------------------------------------------------------------
+// rename_folder (issue #307 - the destination picker's inline rename).
+// ---------------------------------------------------------------------------
+
+#[tokio::test]
+async fn fake_rename_folder_changes_only_the_name() {
+    let store = fake();
+    let root = store.root_id().to_string();
+    let folder = store
+        .ensure_folder(&root, "Old machines", &DriveContext::MyDrive)
+        .await
+        .expect("ensure_folder");
+
+    let renamed = store
+        .rename_folder(&folder.id, "Archive", &DriveContext::MyDrive)
+        .await
+        .expect("rename_folder");
+
+    assert_eq!(renamed.id, folder.id, "id is unchanged by a rename");
+    assert_eq!(renamed.name, "Archive");
+    assert_eq!(renamed.parents, folder.parents, "location is unchanged");
+
+    // ...and list_folder agrees.
+    let listing = store
+        .list_folder(&root, &DriveContext::MyDrive)
+        .await
+        .expect("list root");
+    let entry = listing
+        .iter()
+        .find(|e| e.id == folder.id)
+        .expect("the renamed folder is still listed under the same id");
+    assert_eq!(entry.name, "Archive");
+}
+
+#[tokio::test]
+async fn fake_rename_folder_rejects_an_unknown_id() {
+    let store = fake();
+    let err = store
+        .rename_folder("does-not-exist", "New name", &DriveContext::MyDrive)
+        .await
+        .expect_err("renaming an unknown id must Err");
+    assert!(err.to_string().contains("does-not-exist"));
+}
+
+#[tokio::test]
+async fn fake_rename_folder_refuses_to_rename_a_file() {
+    let store = fake();
+    let root = store.root_id().to_string();
+    let file = store
+        .create(
+            &root,
+            "a.txt",
+            "text/plain",
+            UploadBody::Bytes(Bytes::from_static(b"x")),
+            props(&[]),
+        )
+        .await
+        .expect("create");
+
+    let err = store
+        .rename_folder(&file.id, "b.txt", &DriveContext::MyDrive)
+        .await
+        .expect_err("renaming a FILE via rename_folder must Err");
+    assert!(err.to_string().contains(&file.id));
+}

crates/driven-remote/src/backend.rs

@@ -122,6 +122,33 @@ impl BackendKind {
         }
     }
 
+    /// Whether this backend's destination picker can offer an inline RENAME
+    /// on a folder row (issue #307). Mirrors
+    /// [`crate::RemoteStore::rename_folder`]'s implementations one-for-one -
+    /// this is the flag the picker UI reads to
+    /// decide whether to show the affordance at all, so it must never say
+    /// `true` for a backend whose store still falls through to the trait's
+    /// unsupported default.
+    pub const fn supports_rename(self) -> bool {
+        match self {
+            // `files.update` with just a `name` patch - id and parents
+            // untouched.
+            BackendKind::GoogleDrive => true,
+            // S3 "folders" are key prefixes with no separate identity to
+            // rename; doing so for real would mean copying every object under
+            // the prefix to a new key and deleting the old ones, a bulk
+            // operation the picker's single-row rename does not attempt.
+            BackendKind::S3 => false,
+            // The destination folder has no browsable tree at all
+            // (`supports_folder_picker` is false), so there is no row to
+            // rename.
+            BackendKind::LocalFolder => false,
+            // An SFTP RENAME of the directory, with its sidecar (if any)
+            // moved alongside it.
+            BackendKind::Sftp => true,
+        }
+    }
+
     /// Whether this backend can honour per-source VERSION HISTORY: keeping the
     /// bytes of a superseded file so a point-in-time restore ("restore this
     /// source's files as they were on an earlier date") really returns the older

crates/driven-remote/src/remote_store.rs

@@ -294,6 +294,37 @@ pub trait RemoteStore: Send + Sync {
         drive_context: &DriveContext,
     ) -> anyhow::Result<Vec<RemoteEntry>>;
 
+    /// Renames a folder IN PLACE - its LOCATION (parent) never changes, only
+    /// its display name (issue #307, the destination picker's inline rename).
+    ///
+    /// The returned [`RemoteEntry::id`] is the folder's id to use from now on.
+    /// For Drive this is always the SAME id the caller passed in (a rename is
+    /// a pure metadata patch by opaque file id). For SFTP it can DIFFER: an
+    /// SFTP id is built from encoded path components, so a rename that
+    /// actually changes the encoded name moves the real directory and mints a
+    /// new id at the new path - the caller MUST replace any id it was holding
+    /// with the one this call returns, never assume the input `folder_id`
+    /// still resolves.
+    ///
+    /// The default degrades to an explicit, stably-coded "unsupported" error
+    /// rather than a silent no-op: [`BackendKind::supports_rename`] is what
+    /// tells the picker UI whether to offer the affordance at all, so reaching
+    /// this default means a stale client called it anyway and must be told
+    /// clearly, not left to wonder why nothing changed. S3 "folders" are key
+    /// prefixes with no separate identity to rename (renaming one would mean
+    /// copying every object under the prefix to a new key and deleting the
+    /// old ones - a bulk operation the picker's inline affordance does not
+    /// attempt), so it keeps this default.
+    async fn rename_folder(
+        &self,
+        folder_id: &str,
+        new_name: &str,
+        drive_context: &DriveContext,
+    ) -> anyhow::Result<RemoteEntry> {
+        let _ = (folder_id, new_name, drive_context);
+        anyhow::bail!("remote.rename_unsupported: this destination cannot rename folders")
+    }
+
     /// Enumerates the Shared Drives the authenticated account can access
     /// (Drive `drives.list`), for the destination picker to show Shared Drive
     /// roots beside My Drive (issue #7).