desktop: sortable file list headers, on both panes

[ralyodio]

Click Name, Size or Modified to sort a listing; click the same column again to reverse it. Size and Modified open descending, because nobody clicks Size to find the smallest file.

Both panes get it from the one component, and each keeps its own sort, so a server pane sorts exactly like a local one. It is a client-side reorder of rows the app already holds: no second listing, no SSH round trip, no rsync.

Rules that hold in every direction

• Directories stay above files, so reversing Size does not scatter folders through the list.
• Sorting by size leaves the folder block on name. A directory reports its own inode size rather than the size of its contents, which is why that column already draws an em dash for them.

Two details that would otherwise bite

• Names collate naturally and case-insensitively, so file10 sorts after file2 and Photos does not form a block above every lowercase name. Every comparison falls back to the exact string, because a collator that ignores case calls README and readme equal, and equal entries keep arrival order — which differs between the local lister and SFTP, so the same folder would draw one way on the left and another on the right.
• The keyboard cursor follows its row. It is an index into the visible rows, so re-sorting without moving it left it pointing at whatever row slid into that position.

Verification

• 17 unit tests on the comparator (natural order, folder grouping, both directions per column, an unparseable mtime, tie-breaking, and that the caller's array is not reordered).
• pnpm typecheck clean across all 8 projects; pnpm test 568 passing.
• Driven in headless Chromium under the window's real CSP with a mocked preload bridge: all three columns in both directions, dark and light, and at the 960x600 minimum window. No CSP refusals.

Not included: the CLI's two-pane TUI. It has no column headers to click and its entries carry no mtime, so sorting there is a keybinding plus listing plumbing rather than the same change.

🤖 Generated with Claude Code

https://claude.ai/code/session_012Q2bt449mEJSHoEZzaemCn