Reshape the agent launcher into omarchy agent (#6757)

* Reshape the agent launcher into omarchy agent

omarchy-launch-agent becomes omarchy-agent, with prompts on omarchy-agent-prompt
rather than the bare route: `omarchy agent` is both a command and a group, so a
positional prompt there would shadow any subcommand under it. The launcher takes
flags only and points at `omarchy agent prompt` when handed one.

Every agent window now launches under a fixed org.omarchy.agent app-id instead of
omarchy-launch-tui's default of org.omarchy.<binary>, so one rule floats them all
whichever agent is default.

Omarchy also stops picking an agent for you. omarchy-default-agent prints nothing
until one is chosen, leaving every entry under Setup > Defaults > Agent unchecked,
and a first-run invitation offers to take you there.

* Wordsmith

* Cover the agent routes and the invitation

The route split is the point of the change, so exercise `omarchy agent`,
`omarchy agent prompt`, and a rejected positional prompt through the router
rather than only the binaries behind them.

The invitation gets the same treatment as the Voxtype and fingerprint ones: it
notifies once, opens the agent defaults menu, and leaves both the notification
and the marker alone for anyone who already chose an agent.

* Offer the agent choice from the keybinding

Super + Shift + Ctrl + A now runs `omarchy-agent --pick`, which opens Setup >
Defaults > Agent when nothing is chosen yet. A keypress that writes to stderr
and opens nothing just looks broken.

* Reach existing installs with the agent invitation

first-run installs the invitation hook, and existing accounts marked it complete
long ago, so they would never see it -- while being the accounts most likely to
need it, since the old getter returned opencode implicitly and most have no
agent recorded at all. Post-update hooks run later in the same update, so the
invitation arrives without waiting for another one.

* Say what the Defaults submenus set

Setup > Defaults lists Agent, Browser, Terminal, Editor, but the header inside
each repeated the same bare word, which reads as a category rather than a
setting -- and says nothing at all when the menu is summoned straight into it.
The list keeps its short labels; the headers now name the setting.

default/omarchy/omarchy-menu.jsonc

@@ -128,7 +128,7 @@
   "setup.network.dns.custom": {"icon":"","label":"Custom","checked":"[[ \"$(omarchy-dns)\" == \"Custom\" ]]","action":"omarchy-launch-floating-terminal-with-presentation 'omarchy-dns Custom'"},
   "setup.network.qr": {"icon":"󰐲","label":"QR Code","aliases":["wifi-qr"],"when":"[[ $(omarchy-network-status) == wifi* ]]","action":"omarchy-shell shell summon omarchy.wifiqr"},
   "setup.default": {"icon":"","label":"Defaults","aliases":["default","defaults"]},
-  "setup.default.agent": {"icon":"󰚩","label":"Agent"},
+  "setup.default.agent": {"icon":"󰚩","label":"Agent","title":"Default Agent"},
   "setup.default.agent.claude": {"icon":"󰛄","label":"Claude","checked":"[[ \"$(omarchy-default-agent)\" == \"claude\" ]]","action":"omarchy-default-agent claude"},
   "setup.default.agent.codex": {"icon":"","iconFont":"omarchy","label":"Codex","checked":"[[ \"$(omarchy-default-agent)\" == \"codex\" ]]","action":"omarchy-default-agent codex"},
   "setup.default.agent.copilot": {"icon":"","label":"Copilot","checked":"[[ \"$(omarchy-default-agent)\" == \"copilot\" ]]","action":"omarchy-default-agent copilot"},
@@ -138,7 +138,7 @@
   "setup.default.agent.omp": {"icon":"","iconFont":"omarchy","label":"omp","checked":"[[ \"$(omarchy-default-agent)\" == \"omp\" ]]","action":"omarchy-default-agent omp"},
   "setup.default.agent.opencode": {"icon":"","iconFont":"omarchy","label":"OpenCode","checked":"[[ \"$(omarchy-default-agent)\" == \"opencode\" ]]","action":"omarchy-default-agent opencode"},
   "setup.default.agent.pi": {"icon":"","iconFont":"omarchy","label":"Pi","checked":"[[ \"$(omarchy-default-agent)\" == \"pi\" ]]","action":"omarchy-default-agent pi"},
-  "setup.default.browser": {"icon":"","label":"Browser"},
+  "setup.default.browser": {"icon":"","label":"Browser","title":"Default Browser"},
   "setup.default.browser.chromium": {"icon":"","label":"Chromium","when":"omarchy-cmd-present chromium","checked":"[[ \"$(omarchy-default-browser)\" == \"chromium\" ]]","action":"omarchy-default-browser chromium"},
   "setup.default.browser.chrome": {"icon":"󰊯","label":"Chrome","when":"omarchy-cmd-present google-chrome-stable","checked":"[[ \"$(omarchy-default-browser)\" == \"chrome\" ]]","action":"omarchy-default-browser chrome"},
   "setup.default.browser.brave": {"icon":"󰖟","label":"Brave","when":"omarchy-cmd-present brave","checked":"[[ \"$(omarchy-default-browser)\" == \"brave\" ]]","action":"omarchy-default-browser brave"},
@@ -146,12 +146,12 @@
   "setup.default.browser.edge": {"icon":"󰇩","label":"Edge","when":"omarchy-cmd-present microsoft-edge-stable","checked":"[[ \"$(omarchy-default-browser)\" == \"edge\" ]]","action":"omarchy-default-browser edge"},
   "setup.default.browser.firefox": {"icon":"","label":"Firefox","when":"omarchy-cmd-present firefox","checked":"[[ \"$(omarchy-default-browser)\" == \"firefox\" ]]","action":"omarchy-default-browser firefox"},
   "setup.default.browser.zen": {"icon":"󰖟","label":"Zen","when":"omarchy-cmd-present zen-browser","checked":"[[ \"$(omarchy-default-browser)\" == \"zen\" ]]","action":"omarchy-default-browser zen"},
-  "setup.default.terminal": {"icon":"","label":"Terminal"},
+  "setup.default.terminal": {"icon":"","label":"Terminal","title":"Default Terminal"},
   "setup.default.terminal.alacritty": {"icon":"","label":"Alacritty","when":"omarchy-cmd-present alacritty","checked":"[[ \"$(omarchy-default-terminal)\" == \"alacritty\" ]]","action":"omarchy-default-terminal alacritty"},
   "setup.default.terminal.foot": {"icon":"","label":"Foot","when":"omarchy-cmd-present foot","checked":"[[ \"$(omarchy-default-terminal)\" == \"foot\" ]]","action":"omarchy-default-terminal foot"},
   "setup.default.terminal.ghostty": {"icon":"","label":"Ghostty","when":"omarchy-cmd-present ghostty","checked":"[[ \"$(omarchy-default-terminal)\" == \"ghostty\" ]]","action":"omarchy-default-terminal ghostty"},
   "setup.default.terminal.kitty": {"icon":"","label":"Kitty","when":"omarchy-cmd-present kitty","checked":"[[ \"$(omarchy-default-terminal)\" == \"kitty\" ]]","action":"omarchy-default-terminal kitty"},
-  "setup.default.editor": {"icon":"","label":"Editor"},
+  "setup.default.editor": {"icon":"","label":"Editor","title":"Default Editor"},
   "setup.default.editor.neovim": {"icon":"","label":"Neovim","when":"omarchy-cmd-present nvim","checked":"[[ \"$(omarchy-default-editor)\" == \"nvim\" ]]","action":"omarchy-default-editor nvim"},
   "setup.default.editor.vscode": {"icon":"","label":"VSCode","when":"omarchy-cmd-present code","checked":"[[ \"$(omarchy-default-editor)\" == \"code\" ]]","action":"omarchy-default-editor code"},
   "setup.default.editor.cursor": {"icon":"","label":"Cursor","when":"omarchy-cmd-present cursor","checked":"[[ \"$(omarchy-default-editor)\" == \"cursor\" ]]","action":"omarchy-default-editor cursor"},