Add built-in answer tones and automatic multiple-choice progression

README.md

@@ -25,7 +25,12 @@ Multiple choice: **1–4**. Typed answers: letters/spaces/periods, **Backspace**
 answer. A near spelling offers **R** to edit the existing answer or **V** to
 reveal. Only an exact/accepted alias earns a point. A successfully corrected
 answer earns one point and increments the separate correction count.
-Release keys between presses; **Space** advances after feedback.
+Both modes play a rising tone for a correct answer and a lower, falling tone
+for an incorrect answer, using the CoCo's built-in sound output. No sound
+cartridge is needed. Multiple-choice feedback advances automatically after
+the tone and a 1.5-second reading pause. In typed mode, **Space** advances after
+feedback. Release answer keys before answering the next question; a held key
+cannot submit another answer.
 
 After all 50 questions: **R** paginated missed-answer review, **N** next review
 page, **B** results, **P** play again, **Q** return to BASIC. Replay returns to
@@ -61,11 +66,14 @@ make test                       # host logic and geometry checks
 ```
 
 The editable inputs are `data/states.tsv`, `data/map-seeds.json`,
-`assets/usa-source.svg`, `main.c`, `src/quiz.c` and `src/ui.c`. Generated drawing
+`assets/usa-source.svg`, `main.c`, `src/quiz.c`, `src/ui.c` and the root-level
+`quiz.h`, `ui.h` and `map_data.h` headers. Keeping project headers beside
+`main.c` also makes them available to VCC Plus's isolated build snapshots. Generated drawing
 and state C files are retained for toolchain-only builds. Build outputs are
 ignored. The public MCP JSON-RPC client in `tools/vcc_mcp.py` takes an exported
 private grant path; keep that grant outside Git. See [test evidence](docs/TESTING.md)
-for actual emulator coverage and limitations, and [credits](assets/CREDITS.md)
+for baseline emulator coverage, [feedback tests](docs/FEEDBACK_TESTING.md)
+for the sound and automatic-advance checks, and [credits](assets/CREDITS.md)
 for map attribution and licenses.
 
 For the complete public-MCP regression suite, export a private connection with