tui: the mouse can do everything the keys can

[ralyodio]

The TUI's panes registered click and wheel regions, and that was the whole of it: a click could move the cursor and nothing else. Every directory still had to be entered with a key, every key cap in the footer was a label, the picker's rows and the dialogs' buttons were pictures, and a directory could only be left with the left arrow.

Now, on hqtui 0.5.0 (profullstack/hqtui#86, released as v0.5.0 for this):

• Double-click opens a directory, and a .. row sits above every listing that has a parent, so the way up is on screen. It stays there when a listing failed, because the way out of an unreadable directory must not be keyboard-only. A single click on .. does not move the cursor: there is nowhere on it for the cursor to rest.
• Every key cap in the footer is a button for its action, and the header's direction switches panes while ? help opens the help. A click runs the same private method the key does, under the same rules: a dialog owns the input while it is up, and a running transfer takes nothing but cancel and quit, which is what the footer shows while one runs.
• The endpoint picker chooses a server on one click; a click outside closes it, as it does the help, which also has a close button now. The host-key question answers from its two buttons and from nothing else.
• A finished transfer is dismissed by clicking its panel. A running one is deliberately not cancelled that way; cancel stays on the key bar, spelled out.
• A click on a pane's border, title or empty space focuses it, and a click clears the last message the way a key does.

The row-to-entry arithmetic moved out of the app into the frame: the view resolves a clicked screen row to an index into the visible entries (or -1 for ..) before the app hears about it, and the app's firstVisible bookkeeping is gone.

All of it is asserted by clicking on the rendered frame through hqtui's new test-screen click(), which runs the same hit-test the app does. The view tests click every key cap, both dialogs and ..; the interaction tests drive the real Tui from a click to a changed path, a pointed pane and a quit.

Verified: pnpm build, pnpm -r typecheck, pnpm test (619 tests, 78 in the TUI) against the published @profullstack/hqtui@0.5.0.

🤖 Generated with Claude Code

https://claude.ai/code/session_01DWtLsmAescX4Nb8QiBJd37