lsp: Identify language servers by their configuration (#35270)

- **WIP: reorganize dispositions**
- **Introduce a LocalToolchainStore trait and use it for LspAdapter
methods**

Closes #35782
Closes #27331

Release Notes:

- Python: Improved propagation of a selected virtual environment into
the LSP configuration. This should the make all language-related
features such as Go to definition or Find all references more reliable.

---------

Co-authored-by: Cole Miller <cole@zed.dev>
Co-authored-by: Lukas Wirth <lukas@zed.dev>

crates/extension_host/src/extension_host.rs

@@ -1275,6 +1275,7 @@ impl ExtensionStore {
                         queries,
                         context_provider,
                         toolchain_provider: None,
+                        manifest_name: None,
                     })
                 }),
             );

crates/extension_host/src/headless_host.rs

@@ -163,6 +163,7 @@ impl HeadlessExtensionStore {
                             queries: LanguageQueries::default(),
                             context_provider: None,
                             toolchain_provider: None,
+                            manifest_name: None,
                         })
                     }),
                 );

crates/extension_host/src/wasm_host/wit/since_v0_6_0.rs

@@ -938,7 +938,7 @@ impl ExtensionImports for WasmState {
                             binary: settings.binary.map(|binary| settings::CommandSettings {
                                 path: binary.path,
                                 arguments: binary.arguments,
-                                env: binary.env,
+                                env: binary.env.map(|env| env.into_iter().collect()),
                             }),
                             settings: settings.settings,
                             initialization_options: settings.initialization_options,