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/service-error-classification/dist-cjs/index.js

@@ -1,77 +0,0 @@
-'use strict';
-
-const CLOCK_SKEW_ERROR_CODES = [
-    "AuthFailure",
-    "InvalidSignatureException",
-    "RequestExpired",
-    "RequestInTheFuture",
-    "RequestTimeTooSkewed",
-    "SignatureDoesNotMatch",
-];
-const THROTTLING_ERROR_CODES = [
-    "BandwidthLimitExceeded",
-    "EC2ThrottledException",
-    "LimitExceededException",
-    "PriorRequestNotComplete",
-    "ProvisionedThroughputExceededException",
-    "RequestLimitExceeded",
-    "RequestThrottled",
-    "RequestThrottledException",
-    "SlowDown",
-    "ThrottledException",
-    "Throttling",
-    "ThrottlingException",
-    "TooManyRequestsException",
-    "TransactionInProgressException",
-];
-const TRANSIENT_ERROR_CODES = ["TimeoutError", "RequestTimeout", "RequestTimeoutException"];
-const TRANSIENT_ERROR_STATUS_CODES = [500, 502, 503, 504];
-const NODEJS_TIMEOUT_ERROR_CODES = ["ECONNRESET", "ECONNREFUSED", "EPIPE", "ETIMEDOUT"];
-const NODEJS_NETWORK_ERROR_CODES = ["EHOSTUNREACH", "ENETUNREACH", "ENOTFOUND"];
-
-const isRetryableByTrait = (error) => error?.$retryable !== undefined;
-const isClockSkewError = (error) => CLOCK_SKEW_ERROR_CODES.includes(error.name);
-const isClockSkewCorrectedError = (error) => error.$metadata?.clockSkewCorrected;
-const isBrowserNetworkError = (error) => {
-    const errorMessages = new Set([
-        "Failed to fetch",
-        "NetworkError when attempting to fetch resource",
-        "The Internet connection appears to be offline",
-        "Load failed",
-        "Network request failed",
-    ]);
-    const isValid = error && error instanceof TypeError;
-    if (!isValid) {
-        return false;
-    }
-    return errorMessages.has(error.message);
-};
-const isThrottlingError = (error) => error.$metadata?.httpStatusCode === 429 ||
-    THROTTLING_ERROR_CODES.includes(error.name) ||
-    error.$retryable?.throttling == true;
-const isTransientError = (error, depth = 0) => isRetryableByTrait(error) ||
-    isClockSkewCorrectedError(error) ||
-    TRANSIENT_ERROR_CODES.includes(error.name) ||
-    NODEJS_TIMEOUT_ERROR_CODES.includes(error?.code || "") ||
-    NODEJS_NETWORK_ERROR_CODES.includes(error?.code || "") ||
-    TRANSIENT_ERROR_STATUS_CODES.includes(error.$metadata?.httpStatusCode || 0) ||
-    isBrowserNetworkError(error) ||
-    (error.cause !== undefined && depth <= 10 && isTransientError(error.cause, depth + 1));
-const isServerError = (error) => {
-    if (error.$metadata?.httpStatusCode !== undefined) {
-        const statusCode = error.$metadata.httpStatusCode;
-        if (500 <= statusCode && statusCode <= 599 && !isTransientError(error)) {
-            return true;
-        }
-        return false;
-    }
-    return false;
-};
-
-exports.isBrowserNetworkError = isBrowserNetworkError;
-exports.isClockSkewCorrectedError = isClockSkewCorrectedError;
-exports.isClockSkewError = isClockSkewError;
-exports.isRetryableByTrait = isRetryableByTrait;
-exports.isServerError = isServerError;
-exports.isThrottlingError = isThrottlingError;
-exports.isTransientError = isTransientError;