add .gitignore, clean up generated files from node_modules

Remove from tracking:
- dist/ (build output, regenerated by bun run build.ts)
- node_modules/.pnpm/ (pnpm internal store, 247MB)
- node_modules/.bin/ (executable symlinks)
- node_modules/.ignored/ and .ignored_* (source-map dirs moved aside by pnpm)
- 100 pnpm-installed package symlinks (regenerated by pnpm install)

Keep in tracking:
- Private package stubs not on npm (color-diff-napi, modifiers-napi,
  @ant/claude-for-chrome-mcp, @anthropic-ai/mcpb, @anthropic-ai/sandbox-runtime)
- Source-map extracted packages not installed by pnpm (@grpc/*, @protobufjs/*, etc.)

claude-code-source/node_modules/@smithy/util-stream/dist-cjs/sdk-stream-mixin.js

@@ -1,54 +0,0 @@
-"use strict";
-Object.defineProperty(exports, "__esModule", { value: true });
-exports.sdkStreamMixin = void 0;
-const node_http_handler_1 = require("@smithy/node-http-handler");
-const util_buffer_from_1 = require("@smithy/util-buffer-from");
-const stream_1 = require("stream");
-const sdk_stream_mixin_browser_1 = require("./sdk-stream-mixin.browser");
-const ERR_MSG_STREAM_HAS_BEEN_TRANSFORMED = "The stream has already been transformed.";
-const sdkStreamMixin = (stream) => {
-    if (!(stream instanceof stream_1.Readable)) {
-        try {
-            return (0, sdk_stream_mixin_browser_1.sdkStreamMixin)(stream);
-        }
-        catch (e) {
-            const name = stream?.__proto__?.constructor?.name || stream;
-            throw new Error(`Unexpected stream implementation, expect Stream.Readable instance, got ${name}`);
-        }
-    }
-    let transformed = false;
-    const transformToByteArray = async () => {
-        if (transformed) {
-            throw new Error(ERR_MSG_STREAM_HAS_BEEN_TRANSFORMED);
-        }
-        transformed = true;
-        return await (0, node_http_handler_1.streamCollector)(stream);
-    };
-    return Object.assign(stream, {
-        transformToByteArray,
-        transformToString: async (encoding) => {
-            const buf = await transformToByteArray();
-            if (encoding === undefined || Buffer.isEncoding(encoding)) {
-                return (0, util_buffer_from_1.fromArrayBuffer)(buf.buffer, buf.byteOffset, buf.byteLength).toString(encoding);
-            }
-            else {
-                const decoder = new TextDecoder(encoding);
-                return decoder.decode(buf);
-            }
-        },
-        transformToWebStream: () => {
-            if (transformed) {
-                throw new Error(ERR_MSG_STREAM_HAS_BEEN_TRANSFORMED);
-            }
-            if (stream.readableFlowing !== null) {
-                throw new Error("The stream has been consumed by other callbacks.");
-            }
-            if (typeof stream_1.Readable.toWeb !== "function") {
-                throw new Error("Readable.toWeb() is not supported. Please ensure a polyfill is available.");
-            }
-            transformed = true;
-            return stream_1.Readable.toWeb(stream);
-        },
-    });
-};
-exports.sdkStreamMixin = sdkStreamMixin;