feat: v0.1.0 — Studio Plugin SDK

First release of the SDK that Studio plugins depend on.

What v0.1 ships:

- WIT contract under wit/ (studio-plugin.wit +
  deps/platform/world.wit, both verbatim from
  fai/platform/wit/).
- wit-bindgen 0.36 generate! call with pub_export_macro
  enabled so the emitted __export_studio_plugin_impl! macro
  is reachable from downstream plugin crates.
- export_plugin!(MyType) convenience macro that wraps the
  bindgen-generated impl macro.
- README documenting usage + v0.1 limits (single-world ->
  all-three-hooks-required, no proc-macro yet, edition
  2021 pinned by wit-bindgen output).

What v0.1 doesn't yet do:

- Plugins still declare all three Guest impls (theme,
  translate, output-view). v0.2 splits the WIT into one
  world per hook.
- No #[plugin(...)] proc-macro. v0.2 wraps generate! +
  Guest impl generation into a single attribute.
- Host-side: the hub doesn't yet load studio-plugin-world
  components or expose InvokePlugin RPC — that's the next
  push.

Validated against the in-tree studio-theme-solarized
plugin: 22 KiB stripped .wasm artefact, valid Component
Model, passes wasm-tools component wit inspection.

Signed-off-by: flemming-it <sf@flemming.it>

Cargo.toml

@@ -0,0 +1,57 @@
+# fai-studio-plugin-sdk
+#
+# Ergonomic wrapper around the WIT bindings declared in
+# `wit/studio-plugin.wit`. Studio plugins depend on this crate
+# rather than dealing with raw wit-bindgen output. v0.1 ships
+# WITHOUT the `#[plugin(...)]` proc-macro: plugins write the
+# `export!()` invocation themselves with the structs the SDK
+# provides. The macro lands in v0.2 once the contract is
+# stable enough.
+#
+# Build a plugin:
+#
+#   cargo build --release --target wasm32-wasip2
+#
+# Use:
+#
+#   use fai_studio_plugin_sdk::{export_plugin, theme, ColorScheme,
+#                                PluginError};
+#
+#   struct MyTheme;
+#   impl theme::Guest for MyTheme {
+#       fn theme_for(brightness: String)
+#           -> Result<ColorScheme, PluginError> {
+#           ...
+#       }
+#   }
+#
+#   export_plugin!(MyTheme with_types_in fai_studio_plugin_sdk::bindings);
+
+[package]
+name = "fai-studio-plugin-sdk"
+version = "0.1.0"
+# edition 2021 for now — wit-bindgen 0.36 emits the older
+# `#[link_section]` / `unsafe`-attribute syntax that the
+# edition-2024 compiler rejects. Bump to 2024 when moving
+# to a wit-bindgen version with edition-2024-compatible
+# codegen.
+edition = "2021"
+authors = ["Dr. Stefan Flemming <platform@flemming.ai>"]
+license = "Apache-2.0"
+publish = false
+description = "F∆I Studio Plugin SDK — Rust wrapper for the studio-plugin WIT"
+repository = "https://git.flemming.ai/fai/studio-plugin-sdk"
+rust-version = "1.85"
+
+[lib]
+crate-type = ["rlib"]
+
+[dependencies]
+wit-bindgen = "0.36"
+
+[package.metadata.component]
+package = "fai:studio-plugin-sdk"
+
+[package.metadata.component.target]
+path = "wit"
+world = "studio-plugin"