Fix resource leak in session storage cleanup

[yrobla]

Implements fix by calling Close() on sessions that implement io.Closer before deleting them from storage during cleanup. This prevents connection leaks when vMCP sessions with backend clients expire.

Closes: #3871

[chatgpt-codex-connector]

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[Copilot]

Pull request overview

Fixes session-expiry resource leaks by ensuring expiring sessions that own resources are closed before removal from in-memory storage, with accompanying unit tests validating the new cleanup behavior.

Changes:

• Update LocalStorage.DeleteExpired() to call Close() on sessions that implement io.Closer before deleting them.
• Add unit tests covering io.Closer sessions, non-closer sessions, and Close() error handling.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
pkg/transport/session/storage_local.go	Adds io.Closer detection and Close() invocation during expired-session cleanup, with warning logs on close failure.
pkg/transport/session/storage_test.go	Introduces a closable mock session and adds test cases for closer/non-closer deletion and close-error behavior.

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[codecov]

Codecov Report

❌ Patch coverage is 89.47368% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 68.56%. Comparing base (f0f55c1) to head (b2e839b).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/transport/session/storage_local.go	89.47%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4014      +/-   ##
==========================================
- Coverage   68.60%   68.56%   -0.05%     
==========================================
  Files         444      444              
  Lines       45184    45202      +18     
==========================================
- Hits        31000    30993       -7     
- Misses      11783    11812      +29     
+ Partials     2401     2397       -4     

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

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