feat(vscode-bridge): Copilot Chat bridge (OpenAI facade + JSON-RPC tools)

- Implements VS Code extension per AGENTS.md specification
- OpenAI-style HTTP facade: POST /v1/chat/completions (SSE), GET /v1/models, GET /healthz
- JSON-RPC WebSocket server with methods: mcp.fs.read/list, mcp.search.code, mcp.symbols.list, mcp.edit.applyPatch, mcp.format.apply, mcp.imports.organize
- Copilot Chat integration via vscode.chat.requestChatAccess('copilot')
- Commands: bridge.enable/disable/status with status bar indicator
- Security: localhost-only binding, optional bearer token, read-only by default
- Policy enforcement via optional .agent-policy.yaml
- Ephemeral port management with globalState persistence

Co-Authored-By: Lars Baunwall <larslb@thinkability.dk>

vscode-bridge/node_modules/yaml/dist/stringify/stringify.d.ts

@@ -0,0 +1,21 @@
+import type { Document } from '../doc/Document';
+import type { Alias } from '../nodes/Alias';
+import type { ToStringOptions } from '../options';
+export type StringifyContext = {
+    actualString?: boolean;
+    allNullValues?: boolean;
+    anchors: Set<string>;
+    doc: Document;
+    forceBlockIndent?: boolean;
+    implicitKey?: boolean;
+    indent: string;
+    indentStep: string;
+    indentAtStart?: number;
+    inFlow: boolean | null;
+    inStringifyKey?: boolean;
+    flowCollectionPadding: string;
+    options: Readonly<Required<Omit<ToStringOptions, 'collectionStyle' | 'indent'>>>;
+    resolvedAliases?: Set<Alias>;
+};
+export declare function createStringifyContext(doc: Document, options: ToStringOptions): StringifyContext;
+export declare function stringify(item: unknown, ctx: StringifyContext, onComment?: () => void, onChompKeep?: () => void): string;