feat(tui): expand command palette with daemon controls and fuzzy matching

[bug-ops]

Parent

Part of #581

Summary

Expand the existing TUI command palette with daemon/remote-mode commands, fuzzy matching, keybinding hints, and action commands (quit, help, theme).

Current State

Command palette exists (crates/zeph-tui/src/command.rs, widgets/command_palette.rs) with 7 view-only commands and substring filtering.

Scope

Files: crates/zeph-tui/src/command.rs, crates/zeph-tui/src/widgets/command_palette.rs, crates/zeph-tui/src/app.rs

New commands

Add to TuiCommand enum and command_registry():

id	label	category
daemon:connect	Connect to remote daemon	daemon
daemon:disconnect	Disconnect from daemon	daemon
daemon:status	Show connection status	daemon
session:new	Start new conversation	session
app:quit	Quit application	app
app:help	Show keybindings help	app
app:theme	Toggle theme (dark/light)	app

Daemon commands gated behind #[cfg(feature = "a2a")].

Fuzzy matching

Replace substring filter with fuzzy scoring (character-level match with gap penalty). No new deps — implement inline scorer in filter_commands(). Sort results by score descending.

Keybinding hints

Show bound shortcut (if any) right-aligned in each palette row. Source from Keybindings config in App.

Execute on select

Wire TuiCommand dispatch in App::handle_command() for action commands (Quit, Help, NewSession). Current view commands already dispatch — add the new action variants.

Acceptance Criteria

• Command palette shows 14+ commands (7 existing + 7 new)
• Daemon commands visible only with a2a feature enabled
• Fuzzy matching ranks "sl" → skill:list above mcp:list
• Keybinding hints displayed for commands with shortcuts
• app:quit and app:help execute correctly from palette
• All existing command palette tests pass, new tests for fuzzy matching and new commands