Cross-coordination with flexsiebels/head (paul). m wants more style options
on /imagine/new; flexsiebels has the UI side ready to bump IMAGEN_STYLES
in lib/server/imagen.ts + schemas.ts as soon as the worker accepts them.
styles.yaml: 6 new entries with FLUX-friendly prompt fragments. No code
changes — Apply() and Styles() consume the embedded YAML directly, the
"enum" is dynamic.
prompt_test.go: extend TestStylesContainsAllExpected expectation list
(alphabetical, '3' < 'a' so 3d-render leads).
Total enum: 11 (5 existing + 6 new). flexsiebels delegation message 1669.