Implement binary SAVE/LOAD, INKEY$ extended keys, golden tests, update to v0.10.0

Binary SAVE/LOAD: SAVE now writes tokenized binary by default (0xFF header
format), matching original GW-BASIC behavior. SAVE "file",A for ASCII.
LOAD auto-detects binary vs ASCII from the first byte. Command-line file
loading also auto-detects, so binary .BAS files just work.

INKEY$ extended keys: arrow keys, Home/End/PgUp/PgDn, Insert/Delete, and
F1-F10 now return the correct CHR$(0) + scan_code two-byte sequences per
the IBM PC convention. Refactored event trap key parsing to use tui_read_key()
instead of duplicating escape sequence parsing.

Golden-file regression tests: generated .expected output files for 55 of 58
test programs (3 timing-dependent tests excluded). The test runner now
reports compat match status alongside pass/fail.

Classic programs: added Hamurabi, Lunar Lander, Gunner, and Diamond from
David Ahl's BASIC Computer Games (1978) in tests/classic/ for manual
compatibility testing.

Docs updated with compiler roadmap item and hardware I/O simulator plan.

tests/expected/string_ops.expected

@@ -0,0 +1,14 @@
+HELLO
+WORLD
+WORLD
+ 4
+A
+ 65
+ 3.14
+ 42
+     X
+**********
+FF
+377
+ 7
+ABCDEF