chore(release): prepare v0.11.0

fix(lint): gofmt struct tag alignment in Config

feat(config): support custom themes in config.toml

docs: add dvd scene demo gif to README

chore(demo): add vhs tape for dvd scene

feat(scene): add dvd bouncing logo scene

feat(engine): add fade-to-black transition between scenes

docs: document undocumented config fields in README and config template

fix(test): remove empty branch flagged by staticcheck in starfield test

docs(changelog): record config validation and scene test additions

test(scene): add unit tests for life, maze, pipes, clock, starfield

test(scene): add unit tests for waveform, rain, constellation, particles

feat(config): validate waveform.layers and particles.friction bounds

Merge pull request #43 from LuisMIguelFurlanettoSousa/feat/config-validation

feat(config): add validation for out-of-range config values