Demo — console 2048 (screen-lib entertainment + stress test)

• Type: feature (Track B — demo / library exercise)
• Status: done
• Owner: Track B agent
• Opened: 2026-06-23
• Relation: second consumer of the screen TUI manager (after console_solitaire) — proves the lib is reusable and surfaces any rendering / key-decode bugs. Same shape as the sudoku / solitaire line-UI demos.

Goal

Playable 2048 in the terminal: a 4x4 grid, arrow keys slide + merge tiles, a new tile spawns each move, score accumulates, win at 2048, game over when stuck.

Shape

• Pure engine (g2048.pas): global 4x4 grid; SlideLine (one testable 4-cell compress+merge), Move2048(dir), score, win/over predicates, seeded spawn. Exhaustively unit-tested apart from the UI.
• UI (console_2048.pas): render with screen.pas, keys via ScreenWaitKey (piped input drives it headlessly; EOF quits) — a scripted smoke in lib-test.

Acceptance

• Deterministic engine test (slide/merge cases + a seeded move sequence) in lib-test; a headless scripted UI smoke. Any compiler/lib bug found → ticket, no workaround.

Log

• 2026-06-23 — Done. examples/g2048/g2048.pas (pure engine: SlideLine compress/merge, Move2048 along rows/cols, seeded spawn, win/over) + console_2048.pas (screen-lib UI, arrow keys, colored tiles, score). Tested: test/lib_g2048.pas exhaustive SlideLine + deterministic move/over on ClearBoard/PutTile positions; headless UI smoke (seed 1 + a fixed arrow sequence -> score=8). Both in make lib-test. Second clean consumer of screen.pas — no lib/compiler bugs surfaced this round.

Landed in commit 4198c16.