feat(announcements): add June 4 webinar banner and in-app feed entry

[elliotgunn]

Summary

• Replaces the Kestra Fundamentals banner with the June 4 webinar announcement
• Adds in-app feed entry (feed 97) with webinar image, description, and registration link

Test plan

• Banner shows on site with correct text and registration link
• Feed entry appears in the in-app announcement feed with correct copy and image

[github-actions]

☁️ Cloudflare Worker Preview Deployed!

🔗 https://ks-feat-june-4-webinar-announceme-docs.kestra-io.workers.dev
🔗 https://8a1f3a15-docs.kestra-io.workers.dev

## 🔦 Lighthouse Benchmark

Tested: https://ks-feat-june-4-webinar-announceme-docs.kestra-io.workers.dev on 2026-06-01 20:02 UTC
No baseline available — scores will appear after the first merge to main

Scores (0–100, higher is better)

Page	Performance	Accessibility	Best Practices	SEO
Home	72	83	56	92
Pricing	98	91	56	100
Enterprise	96	82	56	100
Cloud	91	87	56	100
About Us	85	91	56	100
Docs Landing	92	88	56	92
Contribute to Kestra (simple docs)	99	88	56	92
Flow (full featured docs)	97	90	56	92
Blog Index	63	91	56	100
Blog Post (sample)	93	87	56	100
VS Page (sample)	97	88	56	100
Plugins Landing	93	81	56	92
Plugin Page (sample)	95	87	56	100
Plugin Debug Page (sample)	92	87	56	100
Plugin Debug Return Page (sample)	91	88	56	100
Blueprints Landing	93	80	56	92
Blueprint Audit Logs CSV Export	62	86	56	100

Core Web Vitals (lower is better)

Page	LCP	FCP	TBT	CLS	Speed Index
Home	1.39 s	0.71 s	458 ms	0.002	2.11 s
Pricing	0.98 s	0.58 s	34 ms	0.000	0.94 s
Enterprise	1.31 s	0.58 s	12 ms	0.000	0.79 s
Cloud	1.89 s	0.55 s	19 ms	0.033	0.87 s
About Us	2.61 s	0.66 s	29 ms	0.000	0.75 s
Docs Landing	1.68 s	0.61 s	115 ms	0.000	0.99 s
Contribute to Kestra (simple docs)	0.93 s	0.59 s	45 ms	0.000	0.80 s
Flow (full featured docs)	1.01 s	0.56 s	108 ms	0.000	1.13 s
Blog Index	3.75 s	1.44 s	148 ms	0.000	22.95 s
Blog Post (sample)	1.77 s	0.57 s	27 ms	0.000	0.77 s
VS Page (sample)	1.05 s	0.56 s	21 ms	0.064	0.76 s
Plugins Landing	1.05 s	0.56 s	55 ms	0.000	2.39 s
Plugin Page (sample)	1.02 s	0.59 s	85 ms	0.051	1.62 s
Plugin Debug Page (sample)	0.95 s	0.50 s	173 ms	0.001	1.61 s
Plugin Debug Return Page (sample)	1.26 s	0.51 s	139 ms	0.025	1.81 s
Blueprints Landing	1.37 s	0.72 s	36 ms	0.000	1.70 s
Blueprint Audit Logs CSV Export	1.11 s	0.67 s	253 ms	0.485	2.30 s

Legend

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