v0.7.8

Supersedes the partial/broken v0.7.7 release.

- Fix core:common's missing Android/iOS/JS/WasmJS actuals (EnvironmentResolver, DotEnv, FileIO)
- Fix verifyPublishing gate (core:common was never wired into the publish scripts)
- Fix 3 JVM-only API leaks into app:shared's commonMain blocking iOS/WasmJS compile
- Rename graphyn-server -> graphyn-ktor-plugin
- Publish plugins/stable-diffusion as graphyn-plugin-stable-diffusion
- Fix Wan model path/encoder alignment with server-sd; add Wan2.1-I2V-14B-480P template
- Fix color-picker popup anchoring and outside-click dismiss