RHCE review: certification paths + consistent lesson objectives

[bdorlus]

Summary

This PR makes two additive, tightly scoped changes to improve the course scaffolding. No existing prose was rewritten and no FreeBSD content was touched.

1. New "Certification Paths" page

Adds docs/course/certification-paths.md and wires it into the Course: nav (between Syllabus and Capstone). The page keeps the course's distro-agnostic framing while mapping chapters to common Linux certifications:

• RHCSA (EX200, RHEL 9) — table mapping objective areas to real chapters: users/groups (Ch08); permissions/ACL/SELinux (Ch03, Ch05, Ch27); storage/LVM/Stratis (Ch20); systemd services, boot/rescue, root-password recovery (Ch02); scheduled tasks/timers (Ch04); dnf (Ch06); networking/nmcli/firewalld (Ch13, Ch14, Ch27); containers/podman (Ch25); journald logging and chrony (Ch10); tuned (Ch29).
• RHCE (EX294, RHEL 9) — table noting the exam is entirely Ansible automation, mapping to Ch23 (Configuration Management) and Ch07 (scripting), with an honest note that the course gives Ansible an introduction rather than full EX294 depth and pointing learners to Ch23 plus official Red Hat/Ansible docs.
• CompTIA Linux+ (XK0-005) and LPIC-1 — high-level chapter-range mappings.
• A closing "How to use this course for exam prep" section reinforcing the operator loop (Inspect → Change → Verify → Document → Automate) and the Capstone.

Uses Material admonitions (!!! note, !!! tip) consistent with the rest of the course.

2. Learning objectives for 10 lessons

Adds the standard !!! abstract "What you will learn" block (3 specific objectives each) to 10 lessons that were missing it, matching the placement convention used elsewhere in Ch13/Ch20. Every objective is derived from the lesson's actual content; all other content is preserved byte-for-byte.

Lessons touched:

• docs/lessons/13_tcp_ip_networking/13.1_tcp-ip_and_its_relationship_to_the_internet.md
• docs/lessons/13_tcp_ip_networking/13.2_networking_basics.md
• docs/lessons/13_tcp_ip_networking/13.4_ip_addresses-_the_gory_details.md
• docs/lessons/13_tcp_ip_networking/13.5_routing.md
• docs/lessons/13_tcp_ip_networking/13.7_dhcp-_the_dynamic_host_configuration_protocol.md
• docs/lessons/13_tcp_ip_networking/13.8_security_issues.md
• docs/lessons/13_tcp_ip_networking/13.10_linux_networking.md
• docs/lessons/20_storage/20.1_i_just_want_to_add_a_disk!.md
• docs/lessons/20_storage/20.3_storage_hardware_interfaces.md
• docs/lessons/20_storage/20.4_attachment_and_low-level_management_of_drives.md

Verification

• mkdocs build --strict passes (exit 0, no warnings).
• All 10 lessons now contain the objectives block.

🤖 Generated with Claude Code