test: pin command dispatch to C's command.c switch (closes #31)

Audits every case label in C's command.c against this port's dispatch and
leaves the audit behind as a standing test, so the two lists cannot drift
again. A missing dispatch entry is the one porting error that leaves no
trace at build time: the port is function-by-function, so every C function
has a Go counterpart and a dropped key dangles nothing, fails to compile
nowhere, and simply answers "illegal command" the first time a player
presses it. That is how '+' (#11) survived until PR #30 found it by
accident.

Result: no further missing keys. '+' was the only one. Recording that as a
negative result — the class of bug is real, it has now been searched for
exhaustively rather than stumbled upon, and the search came back empty.

commandHandlers is pinned by set equality in both directions. A missing key
is the '+' bug; an extra key is the same bug mirrored, since the likeliest
way to acquire one is promoting a key out of the wizard sub-switch, which
would expose a MASTER debug command in ordinary play. The main-switch keys
that commandHandlers cannot hold - the goto-over re-dispatches, F-to-f, 'a'
and 'm' - are covered separately through dispatchKey, because dropping one
of those is just as silent as dropping a map entry.

Two traps are documented in the file. rogue.h 52-53 defines when as
break;case, so a grep for 'case ' finds six of the eighty labels. And the
main/wizard split is load-bearing: '+' was a divergence in ordinary play,
not just wizard mode, precisely because it is a main-switch key.

Confirms this port targets the MASTER build: all four #ifdef MASTER sites
in command.c are ported unconditionally, as is sticks.c 237.

TODO.md

@@ -34,6 +34,27 @@ wizard commands).
 
 # Completed Steps
 
+- 2026-08-09 Command dispatch audit (`audit/command-switch-coverage`, closes
+  #31): checked every case label in C's `command.c` against this port's
+  dispatch, and left the audit behind as a standing test
+  (`game/dispatch_test.go`) so the two cannot silently drift again. **No further
+  missing keys were found** — `'+'` (#11) was the only one. That is the result,
+  and it is worth recording as a negative: the class of bug exists, it has now
+  been searched for exhaustively rather than stumbled upon, and the search came
+  back empty. Three tables transcribe C's labels with their line numbers:
+  main-switch keys answered from `commandHandlers`, main-switch keys whose arms
+  need `dispatchKey`'s own switch (the `goto over` re-dispatches, `F`-to-`f`,
+  `a`, `m`), and the `if (wizard)` sub-switch. `commandHandlers` is pinned by
+  set equality in **both** directions: a missing key is the `'+'` bug, and an
+  extra key is the same bug mirrored — a MASTER debug command leaking into
+  ordinary play. Two traps make this audit harder than it sounds and are
+  documented in the file: `rogue.h` 52-53 defines `when` as `break;case`, so a
+  grep for `case ` finds six of the eighty labels; and the main/wizard split is
+  load-bearing, since `'+'` was a divergence in ordinary play precisely because
+  it is a main-switch key. Confirms the port targets the MASTER build — all four
+  `#ifdef MASTER` sites in `command.c` are ported unconditionally, as is
+  `sticks.c` 237.
+
 - 2026-08-09 Three small lost C behaviors (`fix/lost-c-behaviors`, closes #13):
   grouped because each is a few lines and all are "restore something the port
   dropped silently". (1) **"what a bizarre schtick!"**, `sticks.c` 237 — the