Fix TypeScript LSP startup without global binary

[BunsDev]

Summary

• Resolve TypeScript LSP startup from custom, workspace-local, CastCodes-managed, then PATH sources instead of requiring a global typescript-language-server.
• Detect workspace-local node_modules/.bin/typescript-language-server and package CLI installs before falling back.
• Surface an actionable Codebase Indexing repair state/button when the TypeScript language server is missing.

Temporary workaround

Until this ships, users can install the TypeScript server locally in the target repo:

npm install -D typescript typescript-language-server

After this change, users can also use Settings > Codebase Indexing > Install/repair TypeScript language server; no global PATH install is required.

Verification

• rustfmt --check app/src/settings_view/code_page.rs crates/lsp/src/config.rs crates/lsp/src/servers/typescript_language_server.rs crates/lsp/src/supported_servers.rs
• git diff --cached --check
• cargo test -p lsp --features local_fs supported_servers::tests
• cargo check -p warp-app --bin cast-codes --features gui,cast-agent

Note: the app compile gate passes with existing warnings in unrelated modules.

[Copilot]

Pull request overview

This PR changes the TypeScript LSP startup path so a globally installed typescript-language-server is no longer required. Resolution now walks user-configured → workspace-local (node_modules/.bin wrapper or the package's cli.mjs) → CastCodes-managed install → PATH, and the Codebase Indexing settings page surfaces an "Install/repair" affordance when the TypeScript server is missing.

Changes:

• Introduce resolve_lsp_binary_config plus LspBinarySource/ResolvedLspBinaryConfig and an actionable missing-binary error message, and add TypeScriptLanguageServerCandidate::find_workspace_binary_config to discover workspace-local installs.
• Rework LspServerConfig::command_and_params to use the new four-source resolution order and carry an optional user-configured CustomBinaryConfig.
• In the Code settings page, detect a repairable TypeScript failure via error-string matching and render an "Install/repair" button, replacing the badge text accordingly.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
crates/lsp/src/supported_servers.rs	Adds resolution types, the actionable error message, the per-server workspace probe dispatch, and unit tests.
crates/lsp/src/servers/typescript_language_server.rs	Adds workspace-local discovery for node_modules/.bin/typescript-language-server and cli.mjs, with --version verification.
crates/lsp/src/config.rs	Stores an optional custom binary on LspServerConfig and rewrites startup resolution to use resolve_lsp_binary_config.
app/src/settings_view/code_page.rs	Adds the repair button + status text for the missing-binary failure and tears down the server before reinstall.

Comments suppressed due to low confidence (1)

app/src/settings_view/code_page.rs:2105

• The repairable-failure detection relies on substring-matching the error message against the human-readable label TYPESCRIPT_LSP_REPAIR_LABEL ("Install/repair TypeScript language server"). This creates a brittle coupling: any future change to the wording in actionable_missing_binary_message (e.g., localization, rephrasing) will silently break the UI's ability to surface the repair button, and conversely any unrelated failure message that happens to contain this phrase will spuriously show the repair UI. Consider propagating this state structurally — for example, by exposing a typed reason on LspState::Failed (a MissingBinary kind or a dedicated error code) — rather than parsing a free-form error string.

    fn is_repairable_lsp_failure(
        &self,
        server_model: Option<&warpui::ModelHandle<LspServerModel>>,
        server_type: LSPServerType,
        app: &AppContext,
    ) -> bool {
        server_type == LSPServerType::TypeScriptLanguageServer
            && server_model.is_some_and(|model| {
                matches!(
                    model.as_ref(app).state(),
                    LspState::Failed { error } if error.contains(TYPESCRIPT_LSP_REPAIR_LABEL)
                )
            })
    }

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[BunsDev]

@copilot apply changes based on the comments in this thread