commands: one grammar for !, merged commands, a settings sheet, two-level help

A `!` now means force or everything and nothing else (`:w!`, `:search!`,
`:export!`, `:logout!`). A command that did a second thing behind its bang
takes a word for it instead: `:space new|name|rm`, `:list name|rm`,
`:task [add]|edit`, `:upload seal`, `:import zip [/]`. `:card` while reading
a document makes a card about it, so `:card!` is gone.

Merged: `:export` downloads what has focus, a file as it is or a document as
markdown (`:download` folded in); `:share [off|new]` replaces `:unshare` and
`:link`, and the list's `s` and `y` give way to it and the info sheet;
`:noh` replaces `:clear`; `:vault [unlock|lock|passwd]` replaces `:unlock`,
`:lock` and `:passwd`; Esc in the list puts down what `m` picked up before it
closes the document, replacing `:unmark`.

The old spellings run as their new lines for one release through a table in
commands.ts; help and Tab leave them out, and the wiki lists them.

A settings sheet (`,` or `:settings`) holds the options, the vault, the
backup, the signed-in browsers, ssh keys and capture tokens. Each row runs
the command a line would. Bare `:set`, `:vault`, `:backup`, `:sessions`,
`:sshkey` and `:token` open it at their part.

`?` shows the keys and commands to start with, flagged in the keymap and the
command table; a second `?` (or `:help all`) shows all of them, and a filter
always searches all of them. Help rows are keyed by key and description, as
two contexts can share a label.

web/src/lib/Rail.svelte

@@ -30,6 +30,7 @@
   const groups = $derived.by((): Door[][] => {
     const cmd: Door = { icon: 'prompt', label: 'Command line', keys: keysOf('global', 'line'), run: () => hooks.openCommandLine(':') }
     const help: Door = { icon: 'help', label: 'Help', keys: keysOf('global', 'help'), run: () => runCommand('help') }
+    const settings: Door = { icon: 'settings', label: 'Settings', keys: keysOf('global', 'settings'), run: () => runCommand('settings') }
 
     const focus = workspace.focus
     const board: Door = workspace.space?.has_board || focus === 'board'
@@ -66,16 +67,16 @@
             icon: 'rename',
             label: card ? 'Rename the card' : 'Rename the list',
             keys: keysOf('board', 'rename'),
-            run: () => hooks.openCommandLine(card ? ':name ' : ':name! '),
+            run: () => hooks.openCommandLine(card ? ':name ' : ':list name '),
           },
           {
             icon: 'trash',
             label: card ? 'Delete the card' : 'Delete the list',
-            keys: card ? keysOf('board', 'delete') : [':list!'],
-            run: () => runCommand(card ? 'delete' : 'list!'),
+            keys: card ? keysOf('board', 'delete') : [':list rm'],
+            run: () => runCommand(card ? 'delete' : 'list rm'),
           },
         ],
-        [cmd, help],
+        [cmd, settings, help],
       ]
     }
 
@@ -112,7 +113,7 @@
         { icon: 'search', label: 'Search this space', keys: keysOf('tree', 'search'), run: () => hooks.openCommandLine('/') },
         { icon: 'search-all', label: 'Search every space', keys: keysOf('global', 'find'), run: () => hooks.openGlobalSearch() },
       ],
-      [cmd, help],
+      [cmd, settings, help],
     ]
   })