fix(player): run gen_block through the language's dialect dispatch (#22)

* fix(player): run gen_block through the language's dialect dispatch

`Apply` stored the raw `gen_block` — `{ generatorId, lines }` — straight onto
`ch.generatorSpec`, so a dialect registered through `registerGenBlockDialect` was never
consulted. The language has the extension point (`parseGenBlock` dispatches to the
registered handler and falls back to a raw shape when there is none); the player just
wasn't calling it.

The effect is silent: a voice that needs the parsed graph, like `matrixFm` or `patch`,
finds `generatorSpec.graph` empty, falls back to a default tone, and plays something
that is not the patch in the file. No error, no substitution recorded.

Additive and non-breaking. `generatorId` and `lines` stay where they were; `kind`,
`tplHeaderId` and `version` are now populated, and `graph` appears when a dialect
provides one. Hosts registering no dialect see the same shape as before.

Note this is necessary but not sufficient. deck-player and @spacedevin/deck-synths each
inline their own copy of @spacedevin/deck — the player against the monorepo working copy,
the synths against 1.5.3 from npm — so they hold two separate dialect registries and a
dialect registered in one is invisible to the other. Deduplicating the language package
is what makes this fix reach across hosts.

* docs(player): the bake does not agree on `square` yet

The comment added with the waveform fallback fix claimed `square` ignores `duty` "on
both sides". It does not. deckpack.rs `pcm_table` has no `square` arm, so the bake falls
through to pulse and honours `duty` — `gen waveform square duty 25` is 50% in the browser
and 25% in the ROM. Say so rather than asserting a parity that isn't there.

Author: spacedevin

packages/player/src/generators/GbaDirectSound.tish

@@ -68,7 +68,10 @@ fn getGbaBuffer(ctx, shape, duty) {
     } else if (shape === "triangle") {
       v = phase < 0.5 ? (phase * 4.0 - 1.0) : (3.0 - phase * 4.0)
     } else if (shape === "square") {
-      // `square` names a 50% wave, so it ignores `duty` on purpose — on both sides.
+      // `square` names a 50% wave, so it ignores `duty` on purpose.
+      // NOTE: the GBA bake does not agree yet — deckpack.rs `pcm_table` has no `square` arm, so it
+      // falls through to pulse, which does honour `duty`. `gen waveform square duty 25` is 50%
+      // here and 25% in the ROM. Tracked on the engine side; do not assume parity for `square`.
       v = phase < 0.5 ? 1.0 : -1.0
     } else if (shape === "sine") {
       v = Math.sin(phase * Math.PI * 2)

packages/player/src/song/Apply.tish

@@ -9,7 +9,7 @@
 // against tish-gba's build-time bake (crates/tish-gba-scenepack/src/deckpack.rs), which is the
 // canonical list for the two chip synths.
 
-import { parseProgram, parseTrackBody, barSelectorMatches, snakeToCamel } from '@spacedevin/deck'
+import { parseProgram, parseTrackBody, barSelectorMatches, snakeToCamel, parseGenBlock } from '@spacedevin/deck'
 import { defaultParamsForGeneratorId, isPortedGeneratorId, knownUnportedGeneratorIds } from '../generators/Registry.tish'
 import { bootDeckRegistries } from './DeckIds.tish'
 
@@ -573,7 +573,23 @@ fn applyTrack(track, index, errors, substitutions, waveTables) {
   }
 
   if (track.genBlocks && track.genBlocks.length > 0) {
-    ch.generatorSpec = track.genBlocks[track.genBlocks.length - 1]
+    let spec = track.genBlocks[track.genBlocks.length - 1]
+    // Run the block through the language's dialect dispatch instead of storing it raw. A host that
+    // registers a `gen_block` dialect (`registerGenBlockDialect`, e.g. matrix_fm or patch) gets the
+    // parsed result here; a host that registers none gets the same shape it always did, plus the
+    // `kind`/`version` the language reports. Storing the raw block meant a registered dialect was
+    // never consulted, so a voice needing the parsed graph fell back to a default tone and played
+    // something that was not the patch in the file.
+    let parsed = parseGenBlock(spec.generatorId, spec.lines)
+    if (parsed) {
+      spec.kind = parsed.kind
+      spec.tplHeaderId = parsed.tplHeaderId
+      spec.version = parsed.version
+      if (parsed.graph !== null && parsed.graph !== undefined) {
+        spec.graph = parsed.graph
+      }
+    }
+    ch.generatorSpec = spec
   }
 
   return ch