feat: studio-theme-solarized v0.1.0 — skeleton

First Studio plugin in the new `studio.*` capability namespace.
SKELETON — does not yet compile.

Why ship the skeleton now:

  * Pins Ethan Schoonover's Solarized palette as two const
    Material 3 ColorScheme arrays so the in-tree reference
    doesn't bike-shed at SDK-integration time.
  * Gives the future fai-studio-plugin-sdk author a concrete
    consumer to validate the generated `#[plugin(theme)]`
    macro output against.
  * Validates that the WIT in fai/platform parses by being a
    real crate that references it.

What it does NOT yet do:

  * Compile. The `fai-studio-plugin-sdk` dependency it points
    at doesn't exist. Tracked in
    `fai/platform/docs/advanced/studio-plugin-sdk.md`.
  * Plug into Studio. The plugin-host module that would
    discover and invoke this component lives in the same
    deferred-Phase-1 work.

What it ships:

  * module.yaml declaring `provides: studio.theme.solarized`
    and `studio_extension.hooks: [theme]`.
  * Cargo.toml with the future SDK dependency commented out,
    crate-type=cdylib, component metadata.
  * src/lib.rs with both Solarized colour palettes
    (SOLARIZED_LIGHT and SOLARIZED_DARK), 14 ARGB tokens
    each in Material 3 order, plus the future `#[plugin]`
    function body commented out and two sanity tests on the
    palette constants.
  * README.md explaining the status and the steps to finish
    the plugin once the SDK ships.

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

.gitignore

@@ -0,0 +1,4 @@
+target/
+**/*.rs.bk
+.DS_Store
+module.wasm