Web tokens.json was reshaped for the SPA theme toggle (#362) with
colors split into dark/light/flat blocks. gen_tokens.dart still
expected a flat string map and threw _Map<String,dynamic> cast
errors in the flutter CI workflow. Read colors.dark + colors.flat
and merge into the existing flat namespace; light variants will be
emitted when the Flutter client gains a theme toggle as part of
#356 parity work. Adds hyphen→camelCase normalization so the new
on-action token surfaces as onAction.
shared/fabledsword.tokens.json mirrors web/src/lib/styles/tokens.json;
assets/error-copy.json mirrors the web's error-code copy table;
assets/svg/album-fallback.svg mirrors the web placeholder. Together
these give Flutter the same visual + copy starting point as the SPA.
tool/gen_tokens.dart emits lib/theme/tokens.dart from the JSON; the
generated file is committed so CI can verify the JSON and the Dart
file haven't drifted (gate added in Task 21).
tool/sync_shared.sh mkdirs the shared/ + assets/ destinations before
copying so the script works on a fresh checkout (the original
plan-text shape only mkdir'd assets/svg).
pubspec.yaml assets block uncommented now that the three asset paths
exist on disk.
bvandeusen