Replace naive exponential backoff with production-grade retry engine:

- Error classification: 18 non-retryable patterns (auth/quota/validation)
  and 24 retryable patterns (network/server/timeout) via extractMessage()
  that handles Error, string, and SSE plain-object shapes
- Fixed backoff schedule [1s, 2.5s, 5s] with ±25% jitter replaces
  unbounded exponential 2^n growth
- fetchWithRetry: retries 5xx/429 with backoff, fails fast on 4xx
- fetchOnce: single fetch for mid-stream reconnects (no double counting)
- streamWithReconnect: emittedContent tracking gates reconnect to prevent
  duplicate content generation; pendingReconnect state machine handles
  clean reconnection flow
- shouldRetry: centralized decision — checks aborted, emittedContent,
  attempt count, and error classification
- buildHttpError: parses JSON error bodies with model ID annotation
- partialOutputError: clear error when reconnect is unsafe
- wrapAsError: normalizes any error shape into Error with ccError/code

SSE error events were silently enqueued as stream parts ({type:"error"})
which the AI SDK treats as ignorable — failures went undetected and the
retry layer never saw them.

Changes:
- Add wrapError() to normalize SSE error objects, strings, and Error
  instances into real Error with ccError and code properties
- toStreamPart("error") now returns null (errors handled at parse level)
- parseStreamEvents: SSE error events call controller.error(wrapError(...))
  instead of controller.enqueue({type:"error"})
- Network read failures in catch block also use controller.error(wrapError(...))
- SSE errors in final buffer chunks also terminate via controller.error()

This ensures the retry layer in model.ts sees real Error objects it can
classify (retryable vs non-retryable) and the AI SDK surfaces failures
to users instead of silently swallowing them.

…nment

Tests that expect 'no key found' behavior were failing when
~/.commandcode/auth.json exists in the test environment.

Mock fs.existsSync to return false for auth file paths
(.commandcode, .pi) while preserving real fs for other paths.
Uses mock.module() with dynamic import so the mock is applied
before auth.ts loads.

…features

- Point to danielxxomg fork repo
- Document retry/backoff, SSE error handling, partial output safety
- Update package.json repo URL and bump version to 0.4.1
- Add local file:// install instructions

…oning variants) for all 50 Command Code models

…ntext

… table