Fix hidden terminal redraw recovery

[emil-e]

Summary

• keep hidden terminal output pending without scheduling redraw timers, then reconcile it from pre-redisplay-functions
• move synchronized-output admission into the renderer's terminal lock and propagate whether rendering completed
• preserve full-redraw and sync-bypass semantics across line mode and Evil integration

Why

A redraw timer could run while a Ghostel buffer had no render window, consuming the redraw request. If an away-and-back tab transition was coalesced between redisplays, window-buffer-change-functions did not observe the reappearance, leaving the materialized buffer stale until another redraw trigger such as resize.

The previous Elisp mode-2026 check was also separate from renderer lock acquisition, allowing synchronized output to begin between the check and rendering.

Verification

• strict Elisp byte compilation
• zig build test
• make checkdoc
• 46 key/invalidation tests
• 16 link/sentinel tests
• 5 Elisp renderer tests
• 83 native renderer tests
• 118 Evil integration tests
• isolated GUI native-gate and hidden-reveal barriers
• git diff --check