ARC-002: Atomic Scene Bundle

Status: implemented Component: Terminal State Implementation: terminal_state.c - implements atomic scene bundle serialization for terminal sessions

Files Created: - src/d3tui/terminal/terminal_state.h (header) - src/d3tui/terminal/terminal_state.c (implementation) - src/tests/test_arc_002.c (test suite)

Key Features: - Versioned binary bundle format with magic number (0x44335455 “D3TU”) - Complete terminal state serialization: dimensions, scrollback, cursor, colors, attributes, modes - Saved cursor state preservation - Alternate screen buffer support - Buffer size calculation for pre-allocation - Comprehensive error handling with error codes

Validation Criteria: - [x] Save complete terminal state to atomic bundle - [x] Load terminal state from bundle - [x] Preserve all cell data (Unicode, colors, attributes) - [x] Preserve cursor state (position, colors, attributes, visibility) - [x] Preserve terminal modes - [x] Preserve scrollback buffer - [x] Handle version compatibility - [x] Handle incompatible dimensions - [x] Handle NULL pointers gracefully - [x] Handle buffer overflow - [x] Pattern info functions

Test Coverage: 12 tests covering all validation criteria

Test File: src/tests/test_arc_002.c (13 test functions: test_arc002_*) Status: implemented Component: Font System Implementation: font_atlas.c - implements per-scene font atlas segmentation

Files Created: - src/d3tui/font/font_atlas.h (header) - src/d3tui/font/font_atlas.c (implementation) - src/tests/test_tex_002.c (test suite)

Key Features: - 7 predefined font segments (BASIC, EXTENDED, JP, CYRILLIC, SYMBOLS, ICONS, CUSTOM) - 4 predefined scene configurations (TERMINAL, TERMINAL_EXTENDED, FULL, MINIMAL) - Scene-based loading: load entire scene’s fonts at once - Character lookup: find which font contains a specific character - No cross-scene sharing (per TEX-002 pattern)

Validation Criteria: - [x] Create segmented font atlases - [x] Load appropriate segments on demand - [x] Switch between segments efficiently - [x] Scene-based loading/unloading - [x] Character lookup across segments - [x] Memory usage within budget (segments loaded only when needed)

Test Coverage: 10 tests covering init, segment info, loading, scene loading, character lookup, pattern info, validation, scene switching, segment count, predefined scenes

Test File: src/tests/test_tex_002.c (10 test functions: test_tex002_*)