fix(plugins): prevent 500 on /meta/plugins/group-undefined.svg

[vfanucci]

Summary

• Fallback to the default plugin OG image (/meta/plugins/{pluginType ?? pluginName}.svg) when the subgroup lookup returns no match, so group-undefined.svg is never emitted into pages.
• Harden the SSR route src/pages/meta/plugins/group-[cls].svg.ts to return 404 instead of crashing the worker when the cls param is missing/literal "undefined", when the metadata API fails, or when no title is returned.

Context

https://kestra.io/meta/plugins/group-undefined.svg was returning a 500. Root cause: in buildPluginPageProps.ts, the OG image URL was built with optional chaining on the subgroup lookup, so when no match was found the URL became literally group-undefined.svg. The route handler then called the metadata API with cls=undefined, the response had no title, and the unhandled access crashed the Cloudflare worker.

Test plan

• Visit a plugin page that previously generated the bad URL — confirm the <meta property="og:image"> now points to the default plugin OG image
• Hit /meta/plugins/group-undefined.svg directly — expect 404, not 500
• Hit a valid /meta/plugins/group-{validCls}.svg — expect the SVG to render as before

🤖 Generated with Claude Code

[vfanucci]

Hello @fdelbrayelle , I don't know if it'a frontor plugins issue, but the /meta/plugins/group-undefined.svg returns a 500. The crawler hit it a lot (339 hits over the last month)

Looks like a fallback icon for plugin groups that aren't matched

[github-actions]

☁️ Cloudflare Worker Preview Deployed!

🔗 https://ks-seo-fix-500-group-undefined-sv-docs.kestra-io.workers.dev
🔗 https://730b5e90-docs.kestra-io.workers.dev

## 🔦 Lighthouse Benchmark

Tested: https://ks-seo-fix-500-group-undefined-sv-docs.kestra-io.workers.dev on 2026-05-27 08:09 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	80	82	56	92
Pricing	98	91	56	100
Enterprise	98	82	56	100
Cloud	91	86	56	100
About Us	84	91	56	100
Docs Landing	93	88	56	92
Contribute to Kestra (simple docs)	98	87	56	92
Flow (full featured docs)	94	90	56	92
Blog Index	75	90	56	100
Blog Post (sample)	99	87	56	100
VS Page (sample)	97	88	56	100
Plugins Landing	92	80	56	92
Plugin Page (sample)	0	87	0	100
Plugin Debug Page (sample)	95	87	56	100
Plugin Debug Return Page (sample)	92	87	59	100
Blueprints Landing	91	80	56	92
Blueprint Audit Logs CSV Export	70	86	56	100

Core Web Vitals (lower is better)

Page	LCP	FCP	TBT	CLS	Speed Index
Home	1.55 s	0.69 s	278 ms	0.002	1.86 s
Pricing	1.00 s	0.62 s	22 ms	0.000	0.90 s
Enterprise	1.12 s	0.59 s	17 ms	0.003	0.75 s
Cloud	1.90 s	0.49 s	32 ms	0.000	0.91 s
About Us	2.91 s	0.63 s	29 ms	0.000	0.91 s
Docs Landing	1.38 s	0.52 s	107 ms	0.000	1.44 s
Contribute to Kestra (simple docs)	1.12 s	0.58 s	35 ms	0.000	0.87 s
Flow (full featured docs)	0.92 s	0.53 s	162 ms	0.001	1.26 s
Blog Index	2.39 s	1.17 s	70 ms	0.001	51.08 s
Blog Post (sample)	0.96 s	0.55 s	8 ms	0.028	0.84 s
VS Page (sample)	1.13 s	0.57 s	22 ms	0.064	0.74 s
Plugins Landing	1.13 s	0.56 s	44 ms	0.000	2.42 s
Plugin Page (sample)	0.00 s	0.00 s	0 ms	0.000	0.00 s
Plugin Debug Page (sample)	0.96 s	0.58 s	116 ms	0.018	1.65 s
Plugin Debug Return Page (sample)	1.17 s	0.61 s	98 ms	0.025	2.19 s
Blueprints Landing	1.56 s	0.75 s	20 ms	0.000	1.82 s
Blueprint Audit Logs CSV Export	1.23 s	0.59 s	135 ms	0.485	2.07 s

Legend

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

[fdelbrayelle]

Hi @vfanucci 👋 Let's add @Piyush-r-bhaskar and @RemiBarthe also as reviewers to be sure :)