Fix FD leak in connSocketBlockingConnect on timeout

[madolson]

Summary

Fix a file descriptor leak in connSocketBlockingConnect() when aeWait() times out.

Bug

When anetTcpNonBlockConnect() succeeds but aeWait() times out (e.g., MIGRATE to an unreachable host), the fd is leaked because it was never assigned to conn->fd. The caller's connClose() checks conn->fd != -1 and skips cleanup.

Fix

Assign conn->fd = fd immediately after anetTcpNonBlockConnect() succeeds, before aeWait(). This way the caller's normal connClose() cleanup path handles the fd on any error, which is consistent with how the rest of the connection lifecycle works.

TLS connections also benefit since connTLSBlockingConnect delegates to this function for the TCP layer.

Reproducer

valkey-cli SET key hello
# Repeat against unreachable host:
for i in $(seq 1 30); do valkey-cli MIGRATE 192.0.2.1 6379 key 0 500; done
# Check: /proc/<pid>/fd shows 30 leaked socket fds

---

This issue was generated by AI but verified, with love, by a human.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.44%. Comparing base (0327c27) to head (7474835).

Additional details and impacted files

@@             Coverage Diff              @@
##           unstable    #3541      +/-   ##
============================================
+ Coverage     76.41%   76.44%   +0.02%     
============================================
  Files           159      159              
  Lines         79927    79927              
============================================
+ Hits          61078    61097      +19     
+ Misses        18849    18830      -19     

Files with missing lines	Coverage Δ
src/socket.c	95.95% <100.00%> (+1.15%)	⬆️

... and 18 files with indirect coverage changes

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[sarthakaggarwal97]

Looks good!