Get settings schema endpoint (#5080)

## Changes

This PR adds `extensionConfiguration/getSettingsSchema` endpoint which
generates json schema file useful for validating cody settings and for
documentation purposes.

## Test plan

1. Build Jenkins [PR
#1972](sourcegraph/jetbrains#1972) with CODY_DIR
set to this PR branch.
2. Run action `Open Cody Settings Editor` (you can use `shift shift` to
find it)
3. Change some Cody settings. E.g. you can try to disable autocomplete:
`"cody.autocomplete.enabled": true`
4. Hit `Ctrl + S` to trigger the config update
5. Try to use autocomplete in some other file and make sure it does not
work.
6. Revert your changes and make sure autocomplete is enabled again.

agent/bindings/kotlin/lib/src/main/kotlin/com/sourcegraph/cody/agent/protocol_generated/CodyAgentServer.kt

@@ -116,6 +116,8 @@ interface CodyAgentServer {
   fun extensionConfiguration_change(params: ExtensionConfiguration): CompletableFuture<AuthStatus?>
   @JsonRequest("extensionConfiguration/status")
   fun extensionConfiguration_status(params: Null?): CompletableFuture<AuthStatus?>
+  @JsonRequest("extensionConfiguration/getSettingsSchema")
+  fun extensionConfiguration_getSettingsSchema(params: Null?): CompletableFuture<String>
   @JsonRequest("textDocument/change")
   fun textDocument_change(params: ProtocolTextDocument): CompletableFuture<TextDocument_ChangeResult>
   @JsonRequest("attribution/search")

agent/src/agent.ts

@@ -5,6 +5,7 @@ import type { Polly, Request } from '@pollyjs/core'
 import { type CodyCommand, ModelUsage, isWindows, telemetryRecorder } from '@sourcegraph/cody-shared'
 import * as vscode from 'vscode'
 import { StreamMessageReader, StreamMessageWriter, createMessageConnection } from 'vscode-jsonrpc/node'
+import packageJson from '../../vscode/package.json'
 
 import {
     type AuthStatus,
@@ -506,6 +507,17 @@ export class Agent extends MessageHandler implements ExtensionClient {
             return result ?? null
         })
 
+        this.registerRequest('extensionConfiguration/getSettingsSchema', async () => {
+            return JSON.stringify({
+                $schema: 'http://json-schema.org/draft-07/schema#',
+                title: 'Schema for Cody settings in the Cody VSCode Extension.',
+                description: 'This prevents invalid Cody specific configuration in the settings file.',
+                type: 'object',
+                allOf: [{ $ref: 'https://json.schemastore.org/package' }],
+                properties: packageJson.contributes.configuration.properties,
+            })
+        })
+
         this.registerNotification('progress/cancel', ({ id }) => {
             const token = vscode_shim.progressBars.get(id)
             if (token) {

vscode/src/jsonrpc/agent-protocol.ts

@@ -233,6 +233,9 @@ export type ClientRequests = {
     // Returns the current authentication status without making changes to it.
     'extensionConfiguration/status': [null, AuthStatus | null]
 
+    // Returns the json schema of the extension confi
+    'extensionConfiguration/getSettingsSchema': [null, string]
+
     'textDocument/change': [ProtocolTextDocument, { success: boolean }]
 
     // Run attribution search for a code snippet displayed in chat.