fix: prevent segmentation fault in CIRA tunnel session timer (#776)

[amarnath-ac]

Initialize APF session timer to prevent nil pointer dereference during connection cleanup.

[codecov]

Codecov Report

❌ Patch coverage is 44.44444% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 39.79%. Comparing base (4d3e507) to head (7e8209f).

Files with missing lines	Patch %	Lines
internal/controller/tcp/cira/tunnel.go	44.44%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #788      +/-   ##
==========================================
+ Coverage   39.67%   39.79%   +0.12%     
==========================================
  Files         112      112              
  Lines       10657    10664       +7     
==========================================
+ Hits         4228     4244      +16     
+ Misses       6047     6038       -9     
  Partials      382      382              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.