fix(docker): handle Kubernetes service-link port env

[dev07060]

Summary

Fixes a Docker entrypoint failure mode in Kubernetes clusters where service-link environment variables can inject a non-numeric CRAWL4AI_PORT value such as tcp://10.0.101.25:80.

This keeps the existing secure-by-default Docker bind posture intact:

• no credential -> loopback-only 127.0.0.1:<port>
• credential/JWT enabled -> existing dual-stack [::]:<port> default
• explicit GUNICORN_BIND in credentialed mode is preserved and does not force CRAWL4AI_PORT parsing

The only behavior change is port normalization before the entrypoint composes its own default bind address. Numeric CRAWL4AI_PORT values still work as before; Kubernetes-style tcp://... service-link values are ignored with a warning and fall back to 11235; other non-numeric values fail fast with a clear error.

I also checked current open PRs for overlap using Kubernetes/k8s/GUNICORN_BIND/CRAWL4AI_PORT/service-link/entrypoint/bind search terms and did not find another PR covering this entrypoint service-link collision.

List of files changed and why

• deploy/docker/entrypoint.sh - add narrow CRAWL4AI_PORT normalization for Kubernetes tcp://... service-link collisions while preserving the existing [::] default and explicit GUNICORN_BIND override behavior.
• deploy/docker/tests/test_security_container_posture.py - add entrypoint regression tests for the dual-stack credentialed bind, service-link fallback with and without credentials, explicit GUNICORN_BIND preservation, and invalid non-service-link port values.

How Has This Been Tested?

• uv run --no-project --with pytest pytest deploy/docker/tests/test_security_container_posture.py -q -k 'TestEntrypoint or TestDockerfile or TestSupervisord or TestCompose' (21 passed, 2 deselected)
• bash -n deploy/docker/entrypoint.sh
• git diff --check

I also attempted the editable project test command, but local dependency setup failed while building scipy==1.13.1 because this machine does not have a Fortran compiler (gfortran) installed.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (N/A: entrypoint behavior is covered by regression tests)
• I have added/updated unit tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes