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/index.js

@@ -1,84 +0,0 @@
-'use strict';
-
-var utilBase64 = require('@smithy/util-base64');
-var utilUtf8 = require('@smithy/util-utf8');
-var ChecksumStream = require('./checksum/ChecksumStream');
-var createChecksumStream = require('./checksum/createChecksumStream');
-var createBufferedReadable = require('./createBufferedReadable');
-var getAwsChunkedEncodingStream = require('./getAwsChunkedEncodingStream');
-var headStream = require('./headStream');
-var sdkStreamMixin = require('./sdk-stream-mixin');
-var splitStream = require('./splitStream');
-var streamTypeCheck = require('./stream-type-check');
-
-class Uint8ArrayBlobAdapter extends Uint8Array {
-    static fromString(source, encoding = "utf-8") {
-        if (typeof source === "string") {
-            if (encoding === "base64") {
-                return Uint8ArrayBlobAdapter.mutate(utilBase64.fromBase64(source));
-            }
-            return Uint8ArrayBlobAdapter.mutate(utilUtf8.fromUtf8(source));
-        }
-        throw new Error(`Unsupported conversion from ${typeof source} to Uint8ArrayBlobAdapter.`);
-    }
-    static mutate(source) {
-        Object.setPrototypeOf(source, Uint8ArrayBlobAdapter.prototype);
-        return source;
-    }
-    transformToString(encoding = "utf-8") {
-        if (encoding === "base64") {
-            return utilBase64.toBase64(this);
-        }
-        return utilUtf8.toUtf8(this);
-    }
-}
-
-exports.Uint8ArrayBlobAdapter = Uint8ArrayBlobAdapter;
-Object.keys(ChecksumStream).forEach(function (k) {
-    if (k !== 'default' && !Object.prototype.hasOwnProperty.call(exports, k)) Object.defineProperty(exports, k, {
-        enumerable: true,
-        get: function () { return ChecksumStream[k]; }
-    });
-});
-Object.keys(createChecksumStream).forEach(function (k) {
-    if (k !== 'default' && !Object.prototype.hasOwnProperty.call(exports, k)) Object.defineProperty(exports, k, {
-        enumerable: true,
-        get: function () { return createChecksumStream[k]; }
-    });
-});
-Object.keys(createBufferedReadable).forEach(function (k) {
-    if (k !== 'default' && !Object.prototype.hasOwnProperty.call(exports, k)) Object.defineProperty(exports, k, {
-        enumerable: true,
-        get: function () { return createBufferedReadable[k]; }
-    });
-});
-Object.keys(getAwsChunkedEncodingStream).forEach(function (k) {
-    if (k !== 'default' && !Object.prototype.hasOwnProperty.call(exports, k)) Object.defineProperty(exports, k, {
-        enumerable: true,
-        get: function () { return getAwsChunkedEncodingStream[k]; }
-    });
-});
-Object.keys(headStream).forEach(function (k) {
-    if (k !== 'default' && !Object.prototype.hasOwnProperty.call(exports, k)) Object.defineProperty(exports, k, {
-        enumerable: true,
-        get: function () { return headStream[k]; }
-    });
-});
-Object.keys(sdkStreamMixin).forEach(function (k) {
-    if (k !== 'default' && !Object.prototype.hasOwnProperty.call(exports, k)) Object.defineProperty(exports, k, {
-        enumerable: true,
-        get: function () { return sdkStreamMixin[k]; }
-    });
-});
-Object.keys(splitStream).forEach(function (k) {
-    if (k !== 'default' && !Object.prototype.hasOwnProperty.call(exports, k)) Object.defineProperty(exports, k, {
-        enumerable: true,
-        get: function () { return splitStream[k]; }
-    });
-});
-Object.keys(streamTypeCheck).forEach(function (k) {
-    if (k !== 'default' && !Object.prototype.hasOwnProperty.call(exports, k)) Object.defineProperty(exports, k, {
-        enumerable: true,
-        get: function () { return streamTypeCheck[k]; }
-    });
-});