Add initial hooks support

[pwang347]

Initial config handling/API work for hooks support

[Copilot]

Pull request overview

Introduces initial “chat hooks” support, including a hooks.json schema + discovery, UI entry points to create/manage hook files, and a proposed API (vscode.chat.executeHook) with main-thread ↔ extension-host plumbing to execute configured hook commands.

Changes:

• Add hook configuration parsing/schema (Copilot hooks.json + Claude settings compatibility) and hook discovery via IPromptsService.getHooks().
• Surface hook configuration in the workbench (new hook file action + “Configure Hooks” picker) and plumb collected hooks into chat agent requests.
• Implement proposed API + RPC wiring + Node extension-host execution for hook commands, with tests for parsing/compat and ext-host execution.

Reviewed changes

Copilot reviewed 35 out of 36 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
src/vscode-dts/vscode.proposed.chatHooks.d.ts	Adds proposed chatHooks API typings (hook types, execution, result).
src/vs/workbench/contrib/chat/test/common/promptSyntax/service/mockPromptsService.ts	Updates prompts service mock to satisfy new getHooks API.
src/vs/workbench/contrib/chat/test/common/promptSyntax/hookSchema.test.ts	Unit tests for hook type normalization + hook command resolution.
src/vs/workbench/contrib/chat/test/common/promptSyntax/hookClaudeCompat.test.ts	Unit tests for Claude hook compatibility parsing/mapping.
src/vs/workbench/contrib/chat/test/common/chatService/chatService.test.ts	Stubs IPromptsService for chat service tests after DI change.
src/vs/workbench/contrib/chat/common/promptSyntax/service/promptsServiceImpl.ts	Implements hook file discovery/parsing + caching via getHooks().
src/vs/workbench/contrib/chat/common/promptSyntax/service/promptsService.ts	Extends IPromptsService with getHooks().
src/vs/workbench/contrib/chat/common/promptSyntax/promptTypes.ts	Adds hook docs URL + language-id mapping for hook prompt type.
src/vs/workbench/contrib/chat/common/promptSyntax/languageProviders/promptValidator.ts	Updates validator attribute sets to handle new hook prompt type.
src/vs/workbench/contrib/chat/common/promptSyntax/hookSchema.ts	Defines hook schema/types and helpers for command resolution/labels.
src/vs/workbench/contrib/chat/common/promptSyntax/hookCompatibility.ts	Adds format detection + parsing dispatch across supported formats.
src/vs/workbench/contrib/chat/common/promptSyntax/hookClaudeCompat.ts	Implements Claude settings.json hook parsing compatibility.
src/vs/workbench/contrib/chat/common/promptSyntax/config/promptFileLocations.ts	Adds hook file locations/types (hooks.json + .claude settings).
src/vs/workbench/contrib/chat/common/promptSyntax/config/config.ts	Introduces settings keys for hook file locations + enablement.
src/vs/workbench/contrib/chat/common/promptSyntax/chatPromptFilesContribution.ts	Extends prompt file listing command to include hooks.
src/vs/workbench/contrib/chat/common/participants/chatAgents.ts	Plumbs collected hooks into IChatAgentRequest.
src/vs/workbench/contrib/chat/common/hooksExecutionService.ts	Adds main-thread service abstraction for executing hooks via proxy.
src/vs/workbench/contrib/chat/common/chatService/chatServiceImpl.ts	Collects hooks via prompts service and attaches to chat requests.
src/vs/workbench/contrib/chat/browser/promptSyntax/promptFileActions.ts	Registers hook-related actions alongside other prompt actions.
src/vs/workbench/contrib/chat/browser/promptSyntax/pickers/promptFilePickers.ts	Adds hook help button support in prompt pickers.
src/vs/workbench/contrib/chat/browser/promptSyntax/pickers/askForPromptSourceFolder.ts	Adds hook-related picker strings + disallows copy/move for hooks.
src/vs/workbench/contrib/chat/browser/promptSyntax/newPromptFileActions.ts	Adds “New Hook File…” command to create/extend hooks.json.
src/vs/workbench/contrib/chat/browser/promptSyntax/hookUtils.ts	Adds helper to select newly-added hook command in JSON content.
src/vs/workbench/contrib/chat/browser/promptSyntax/hookActions.ts	Adds “Configure Hooks…” action and quick pick UI for hook entries.
src/vs/workbench/contrib/chat/browser/chat.contribution.ts	Registers hook JSON schema + hook-related configuration + service singleton.
src/vs/workbench/api/test/node/extHostHooks.test.ts	Adds tests for extension-host hook execution behavior.
src/vs/workbench/api/node/extHostHooksNode.ts	Implements Node extension-host hook execution via child_process.
src/vs/workbench/api/node/extHost.node.services.ts	Registers IExtHostHooks singleton for node extension host.
src/vs/workbench/api/common/extHostTypes.ts	Adds ChatHookResultKind to ext host types.
src/vs/workbench/api/common/extHostHooks.ts	Defines ext-host hooks service interface + RPC shape.
src/vs/workbench/api/common/extHostChatAgents2.ts	Stores hooks on in-flight requests + exposes getHooksForSession.
src/vs/workbench/api/common/extHost.protocol.ts	Adds RPC identifiers and DTO for hook execution results.
src/vs/workbench/api/common/extHost.api.impl.ts	Wires proposed vscode.chat.executeHook to ext-host implementation.
src/vs/workbench/api/browser/mainThreadHooks.ts	Main-thread customer that forwards executions to the extension host.
src/vs/workbench/api/browser/extensionHost.contribution.ts	Registers main-thread hooks customer.
src/vs/platform/extensions/common/extensionsApiProposals.ts	Registers chatHooks proposal + version.

Comments suppressed due to low confidence (1)

src/vs/workbench/contrib/chat/browser/promptSyntax/hookUtils.ts:69

• Related to the above: treating any '}' while bracketDepth===1 as the end of the target object can trigger on nested object closures (like the end of an env object), causing early termination and incorrect/undefined selections. This should be based on proper JSON structure rather than character scanning.

			} else if (char === '}' && inTargetObject && bracketDepth === 1) {
				// End of the target object, search for field within this object
				for (let j = targetObjectStartLine; j <= i; j++) {