chore: bump DefaultFirewallVersion to v0.24.5

[Mossaka]

Summary

Bump DefaultFirewallVersion in pkg/constants/constants.go from v0.24.3 to v0.24.5.

Why

v0.24.5 includes a fix that eliminates a 10-second container shutdown delay per AWF invocation (github/gh-aw-firewall#1373). This saves ~20s per workflow run (main agent + threat detection).

Changes in v0.24.4 and v0.24.5 since v0.24.3:

• v0.24.4: fix: update vulnerable dependencies (flatted, markdownlint-cli2)
• v0.24.5: fix: eliminate 10s container shutdown delay — switches api-proxy Dockerfile from shell-form CMD to exec form, adds shutdown_lifetime 0 to squid config, and adds stop_grace_period: 2s to both containers

What to change

1. Update pkg/constants/constants.go line 341:

   const DefaultFirewallVersion Version = "v0.24.5"

2. Update any test expectations that reference the old version
3. Run make recompile to update all workflow lock files
4. Run make test-unit and make lint to verify

References

• Release: https://github.com/github/gh-aw-firewall/releases/tag/v0.24.5
• Shutdown fix PR: fix: eliminate 10s container shutdown delay gh-aw-firewall#1373
• Performance report: Performance report #21703