Fix missing horizontal bars and ensure consistent box widths in archive page wireframe

[Copilot]

Fixed missing horizontal bars in POST 3 and POST 4 box headers and made all POST box headers consistent with other section widths in the wireframe.

Changes made:

• Extended POST box headers from 14 to 18 dashes (┌─ POST X ──────────────────┐)
• Updated corresponding closing lines to match the new width (└───────────────────────────┘)
• Applied changes to all four POST boxes (POST 1, 2, 3, and 4) for consistency
• Now all POST boxes have 29-character total width, matching other major sections

Before:

│ │ │ │ ┌─ POST 3 ──────────────┐ │ │ │  (23 characters)

After:

│ │ │ │ ┌─ POST 3 ──────────────────┐ │ │ │  (29 characters)

This ensures visual consistency across the wireframe and provides proper horizontal borders for all POST sections.

---

💬 Share your feedback on Copilot coding agent for the chance to win a $200 gift card! Click here to start the survey.

[github-actions]

🦙 MegaLinter status: ❌ ERROR

Descriptor	Linter	Files	Fixed	Errors	Warnings	Elapsed time
❌ ACTION	actionlint	5		6	0	0.08s
✅ BASH	bash-exec	1		0	0	0.0s
✅ BASH	shellcheck	1		0	0	0.05s
⚠️ BASH	shfmt	1		1	0	0.0s
❌ C	cppcheck	8		8	0	0.27s
❌ CPP	cppcheck	8		8	0	0.3s
✅ JSON	npm-package-json-lint	yes		no	no	0.37s
✅ JSON	v8r	12		0	0	8.27s
❌ MARKDOWN	markdown-link-check	740		218	0	786.83s
✅ REPOSITORY	gitleaks	yes		no	no	13.59s
✅ REPOSITORY	git_diff	yes		no	no	0.3s
❌ REPOSITORY	grype	yes		2	no	34.16s
✅ REPOSITORY	secretlint	yes		no	no	42.62s
✅ REPOSITORY	syft	yes		no	no	1.83s
✅ REPOSITORY	trivy-sbom	yes		no	no	3.15s
✅ REPOSITORY	trufflehog	yes		no	no	4.63s
✅ XML	xmllint	1		0	0	199.22s
✅ YAML	v8r	13		0	0	7.35s

See detailed report in MegaLinter reports