Implement textDocument/hover with symbol analysis for types, constructors,
lets, and builtins; pin the wasm Gleam input to 8d88cf3a and add a Go example.

Wire tangled.org/nandi.uk/gleam (wasm) as an input, expose packages.gleam
and packages.zed-extension (prebuilt Gleam guest), and nix run install helper.

Explain that Zed Install Dev Extension always cargo-builds a Rust guest, so
src/glint.rs is temporary; pure Gleam remains the target via the wasm fork.

Ship editors/zed (Rust guest for Install Dev Extension, Gleam sketch for
future pure Wasm), language-server sources, and README instructions linking
the Gleam wasm fork on Tangled.