TUI: deep split of tui.ts and tui-command-handlers.ts

[ApiliumDevTeam]

Summary

Closes the file-size reduction follow-up from #74. Both monolithic TUI files are split below the ~500 LOC guideline without changing any observable behavior.

tui.ts (883 → 591 LOC) — three modules extracted from runTui():

• tui-status-renderer.ts (301 LOC): status/footer rendering, busy/idle timers, waiting-status animation. Owns activityStatus, connectionStatus, isConnected, statusTimeout — the state object delegates via late-bound getters/setters.
• tui-keybindings.ts (119 LOC): editor callbacks (onEscape, onCtrlC/D/O/L/G/P/T, onShiftTab). Mutable state accessed via TuiStateAccess.
• tui-connection.ts (121 LOC): gateway client lifecycle (onEvent, onConnected, onDisconnected, onGap). Pairing/gateway-down hint flags are internal.

The remaining 591 LOC is primarily the state object definition (~170 LOC of getters/setters) plus essential wiring — extraer eso a una factory añade indirección sin claridad.

tui-command-handlers.ts (1402 → 351 LOC) — 7 command group modules + dispatcher:

• tui-cmd-session.ts: agent, session, model, new, reset, search
• tui-cmd-config.ts: think, verbose, reasoning, elevated, activation, usage, context
• tui-cmd-display.ts: style, theme, diff, permission, fast, tools
• tui-cmd-clipboard.ts: copy, export
• tui-cmd-ecosystem.ts: plan, kg, trace, team, tasks, workflow, rules, mailbox, sync, mouse
• tui-cmd-teleport.ts: teleport (export/import)
• tui-cmd-misc.ts: help, status, undo, abort, settings, bug, init, exit, quit, onboard, batch, vim, compact, default
• tui-cmd-types.ts: shared CommandHandlerContext (extended with closures) + CommandGroupHandler type

The dispatcher iterates over the groups until one returns true (handled). The public API (createCommandHandlers → { handleCommand, sendMessage, ... }) is unchanged.

Test plan

• pnpm tsgo — 0 errors
• pnpm lint — 0 errors, 359 warnings
• pnpm exec vitest run src/tui/ — 512 passed, 1 skipped, 0 failed
• All 34 tui-command-handlers.test.ts tests pass without modification (public API preserved)
• Rebased on latest origin/dev (includes FTS5 session search and skill curator lifecycle #77 FTS5 search) — no conflicts, searchSessions interface unchanged