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

@@ -49,7 +49,7 @@ wizard commands).
   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 ten of the eighty labels; and the main/wizard split is
+  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

game/dispatch_test.go

@@ -23,7 +23,7 @@ import (
 //	#define otherwise	break;default
 //
 // The labels are therefore written "when 'x':", and a grep for "case "
-// finds ten of the eighty. CTRL is extern.h:113, (c & 037); ESCAPE is
+// finds six of the eighty. CTRL is extern.h:113, (c & 037); ESCAPE is
 // rogue.h:121, 27.
 //
 // There are two switches and the split between them is load-bearing. A