docs(link-check-ci): add script to ensure link standard

[aj-emerich]

Closes #3843

[github-actions]

☁️ Cloudflare Worker Preview Deployed!

🔗 https://ks-docs-add-link-checker-script-docs.kestra-io.workers.dev
🔗 https://e47c4050-docs.kestra-io.workers.dev

## 🔦 Lighthouse Benchmark

Tested: https://ks-docs-add-link-checker-script-docs.kestra-io.workers.dev on 2026-05-08 10:18 UTC
Compared against main baseline from 2026-04-10

Scores (0–100, higher is better)

Page	Performance	Accessibility	Best Practices	SEO
Home	76 🟢 +19	82	59	92
Pricing	95	91	59	100
Enterprise	93	82	59	100
Cloud	87	86	59	100
About Us	80 🔻 -15	91	59	100
Docs Landing	93	88	59	92
Contribute to Kestra (simple docs)	92	87	59	92
Flow (full featured docs)	84	90	59	92
Blog Index	66 🔻 -15	90	59	100
Blog Post (sample)	95	87	59	100
VS Page (sample)	93	91	59	100
Plugins Landing	87	80	59	92
Plugin Page (sample)	94	87	59	100
Plugin Debug Page (sample)	94	87	59	100
Plugin Debug Return Page (sample)	91	87	59	100
Blueprints Landing	88	80	59	92
Blueprint Audit Logs CSV Export	0 🔻 -61	86	0 🔻 -59	100

Core Web Vitals (lower is better)

Page	LCP	FCP	TBT	CLS	Speed Index
Home	1.35 s 🟢	0.89 s 🟢	346 ms 🔻	0.002	2.06 s 🟢
Pricing	1.24 s	0.70 s	123 ms 🔻	0.000	0.81 s
Enterprise	1.56 s	0.75 s	108 ms 🔻	0.003	0.90 s 🟢
Cloud	2.28 s	0.69 s	102 ms 🔻	0.000	0.90 s
About Us	3.52 s 🔻	0.70 s	68 ms	0.000	1.08 s
Docs Landing	1.28 s	0.66 s 🟢	127 ms	0.000	1.34 s
Contribute to Kestra (simple docs)	1.39 s	0.79 s	147 ms 🔻	0.000	1.06 s
Flow (full featured docs)	1.55 s	0.78 s	261 ms 🔻	0.000	1.24 s
Blog Index	5.29 s 🔻	0.61 s	71 ms 🔻	0.000	19.87 s 🔻
Blog Post (sample)	1.33 s	0.61 s	103 ms 🔻	0.000	0.75 s
VS Page (sample)	1.13 s	0.65 s	156 ms 🔻	0.064	0.76 s 🟢
Plugins Landing	1.21 s 🟢	0.68 s	160 ms 🔻	0.000	2.63 s 🔻
Plugin Page (sample)	1.08 s	0.67 s	74 ms 🔻	0.051	1.85 s
Plugin Debug Page (sample)	1.08 s	0.59 s	87 ms	0.001	1.86 s 🔻
Plugin Debug Return Page (sample)	1.24 s	0.71 s	123 ms 🔻	0.025	1.93 s 🔻
Blueprints Landing	1.70 s	0.88 s	42 ms 🟢	0.000	2.05 s 🔻
Blueprint Audit Logs CSV Export	0.00 s 🟢	0.00 s 🟢	0 ms 🟢	0.000 🟢	0.00 s 🟢

Legend

🟢 improved  ·  🔻 regressed  ·  (blank) no significant change
Score threshold: ±10 pts  ·  Metric threshold: ±30% of baseline