Add pink-spoon extension

[janisharbs]

Summary

pink-spoon fills the gap between ruby-lsp and Sorbet RBI files.

ruby-lsp gives you IDE features based on source code it can parse. It doesn't read Sorbet's generated .rbi files, so type signatures from gems, T::Struct, and other Sorbet-annotated code are invisible to it.

pink-spoon indexes everything under sorbet/rbi/ and feeds that type information back into ruby-lsp:

• Hover shows the Sorbet sig for the method under the cursor, pulled from RBI, with doc comments from gem source
• Go to definition jumps to the .rbi entry (or straight to gem source when a # source:// comment exists)
• Completion suggests typed methods from RBI when the receiver type is known (e.g. SomeClass.)
• Code lens adds Run / Run in watch mode buttons next to RSpec describe/context/it blocks

Bonus: it walks extend/include/superclass chains, so mixin methods resolve correctly rather than coming up empty.

Done

• add the pink-spoon extension to the marketplace registry
• register the public janisharbs/pink-spoon repository as a submodule
• publish version 0.1.1