Reframe seed-article banners as community contribution invitations

The 35 articles still in their seed form previously carried a banner
reading "Seed article. ... Domain stewards should expand, restructure,
and refine as needed." For a community preview, that phrasing reads as
"TODO left in production" to first-time visitors.

Replace all three banner variants (performance-seeded, security-seeded,
community-ported) with a single positive invitation:

> Contributions welcome — open a PR to refine or extend this article.

Content and structure of the articles are unchanged; only the leading
quote block differs. Articles that had their banner fully stripped in
the earlier triage pass (the showcase-grade ten) are unaffected.

microsoft/knowledge/security/compose-secrets-with-secretstrsubstno.md

@@ -9,7 +9,7 @@ application-area: [all]
 
 # Compose secrets with SecretStrSubstNo
 
-> **Seed article.** Converted from an existing security-review prompt to bootstrap the BCQuality security corpus. Domain stewards should expand, restructure, and refine as needed.
+> Contributions welcome — open a PR to refine or extend this article.
 
 ## Description
 

microsoft/knowledge/security/do-not-expose-sensitive-data-in-event-publishers.md

@@ -9,7 +9,7 @@ application-area: [all]
 
 # Do not expose sensitive data in event publishers
 
-> **Seed article.** Converted from an existing security-review prompt to bootstrap the BCQuality security corpus. Domain stewards should expand, restructure, and refine as needed.
+> Contributions welcome — open a PR to refine or extend this article.
 
 ## Description
 

microsoft/knowledge/security/follow-least-privilege-in-permission-sets.md

@@ -9,7 +9,7 @@ application-area: [all]
 
 # Follow least privilege in permission sets
 
-> **Seed article.** Converted from an existing security-review prompt to bootstrap the BCQuality security corpus. Domain stewards should expand, restructure, and refine as needed.
+> Contributions welcome — open a PR to refine or extend this article.
 
 ## Description
 

microsoft/knowledge/security/never-hardcode-secrets-in-al.md

@@ -9,7 +9,7 @@ application-area: [all]
 
 # Never hardcode secrets in AL
 
-> **Seed article.** Converted from an existing security-review prompt to bootstrap the BCQuality security corpus. Domain stewards should expand, restructure, and refine as needed.
+> Contributions welcome — open a PR to refine or extend this article.
 
 ## Description
 

microsoft/knowledge/security/prefer-azure-key-vault-for-production-secrets.md

@@ -9,7 +9,7 @@ application-area: [all]
 
 # Prefer Azure Key Vault for production secrets
 
-> **Seed article.** Converted from an existing security-review prompt to bootstrap the BCQuality security corpus. Domain stewards should expand, restructure, and refine as needed.
+> Contributions welcome — open a PR to refine or extend this article.
 
 ## Description
 

microsoft/knowledge/security/use-indirect-permissions-for-elevated-access.md

@@ -9,7 +9,7 @@ application-area: [all]
 
 # Use indirect permissions for elevated access
 
-> **Seed article.** Converted from an existing security-review prompt to bootstrap the BCQuality security corpus. Domain stewards should expand, restructure, and refine as needed.
+> Contributions welcome — open a PR to refine or extend this article.
 
 ## Description
 

microsoft/knowledge/security/use-inherent-permissions-to-grant-minimal-access.md

@@ -9,7 +9,7 @@ application-area: [all]
 
 # Use InherentPermissions to grant minimal access
 
-> **Seed article.** Converted from an existing security-review prompt to bootstrap the BCQuality security corpus. Domain stewards should expand, restructure, and refine as needed.
+> Contributions welcome — open a PR to refine or extend this article.
 
 ## Description
 

microsoft/knowledge/security/use-isolated-storage-for-module-and-company-secrets.md

@@ -9,7 +9,7 @@ application-area: [all]
 
 # Use IsolatedStorage for module and company secrets
 
-> **Seed article.** Converted from an existing security-review prompt to bootstrap the BCQuality security corpus. Domain stewards should expand, restructure, and refine as needed.
+> Contributions welcome — open a PR to refine or extend this article.
 
 ## Description
 

microsoft/knowledge/security/use-nondebuggable-when-parsing-secrets.md

@@ -9,7 +9,7 @@ application-area: [all]
 
 # Use NonDebuggable when parsing secrets
 
-> **Seed article.** Converted from an existing security-review prompt to bootstrap the BCQuality security corpus. Domain stewards should expand, restructure, and refine as needed.
+> Contributions welcome — open a PR to refine or extend this article.
 
 ## Description