examples: expand timeout scenarios

[Rememorio]

Summary

• Expand the timeout example into a client -> forward server -> backend server call chain.
• Add generated public Chat proto stubs for the timeout flow.
• Document full-link timeout scenarios without relying on internal services.

Tests

• go test ./features/timeout/... -count=1 from examples/
• go test ./... -count=1 from examples/
• git diff --check main...HEAD
• Scanned changed files for internal-only links and local paths

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.42410%. Comparing base (53fe5d2) to head (01a7f54).

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main        #245         +/-   ##
===================================================
+ Coverage   85.30338%   85.42410%   +0.12071%     
===================================================
  Files            215         215                 
  Lines          19052       19052                 
===================================================
+ Hits           16252       16275         +23     
+ Misses          2118        2102         -16     
+ Partials         682         675          -7     

Flag	Coverage Δ
unittests	85.42410% <ø> (+0.12071%)	⬆️

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[WineChord]

LGTM