fix(pager): handle pager exit and broken pipe gracefully

[pamburus]

Fix Pager Exit and Broken Pipe Handling

Summary

Fixes issue where the application would not exit cleanly when the pager closes or when output write operations fail.

Changes

• Application now exits cleanly when pager is closed (e.g., pressing 'q' in less)
• Graceful exit on broken pipe when output destination closes early
• No error messages or hanging processes when pager terminates

[codecov]

Codecov Report

❌ Patch coverage is 92.89100% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.53%. Comparing base (4279eb3) to head (6ac0fa2).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
crates/pager/src/lib.rs	89.24%	10 Missing ⚠️
src/main.rs	92.10%	3 Missing ⚠️
src/signal_unix.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1330      +/-   ##
==========================================
+ Coverage   88.06%   88.53%   +0.47%     
==========================================
  Files          67       68       +1     
  Lines       11625    11780     +155     
==========================================
+ Hits        10238    10430     +192     
+ Misses       1387     1350      -37     

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