Preserve hooked stream timeout failures

[binaryfire]

Native PHP returns false when a blocking stream read or write times out without transferring data. The coroutine stream hook converted these failures into zero-byte results, so fread() returned an empty string and fwrite() returned 0.

Keep timeout failures as errors while preserving the existing nonblocking, EOF, and partial-I/O behavior.

The read regression tightens the existing timeout test. The write regression fills a local socket pair, then verifies the blocking timeout returns false without marking the stream as EOF.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.24%. Comparing base (07606e5) to head (53120fb).

Additional details and impacted files

@@            Coverage Diff             @@
##              6.1    #6236      +/-   ##
==========================================
- Coverage   86.24%   86.24%   -0.01%     
==========================================
  Files         110      110              
  Lines       16790    16790              
  Branches     2980     2980              
==========================================
- Hits        14481    14480       -1     
- Misses       2309     2310       +1     

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