docs: replace dead article links with live sources (#10404)

Per maintainer guidance to prefer fresh content over archived files:

- gafferongames udp-vs-tcp (2 files): updated to the article's current
  location at gafferongames.com/post/udp_vs_tcp/
- transaction script: the personal blog post is gone; linked Martin
  Fowler's canonical Transaction Script page instead
- postgres buffer manager: the dev.to summary was deleted; linked the
  original book chapter it summarized (The Internals of PostgreSQL,
  ch.8 Buffer Manager)
- dropped two resource lines whose sources are gone entirely with no
  replacement: businessdesign.org Business Model Inspirator (section
  removed from the site) and a digger.dev Terraform/Jenkins post
  (domain dead, label was also corrupted)

All replacement URLs verified to resolve (HTTP 200).

Co-authored-by: Weijian He <230282609+Madin-H23@users.noreply.github.com>

roadmaps/postgresql-dba/content/buffer-management@KeBUzfrkorgFWpR8A-xmJ.md

@@ -6,4 +6,4 @@ Visit the following resources to learn more:
 
 - [@official@pg_buffercache](https://www.postgresql.org/docs/current/pgbuffercache.html)
 - [@official@Write Ahead Logging](https://www.postgresql.org/docs/current/wal-intro.html)
-- [@article@Buffer Manager](https://dev.to/vkt1271/summary-of-chapter-8-buffer-manager-from-the-book-the-internals-of-postgresql-part-2-4f6o)
+- [@article@Buffer Manager](https://www.interdb.jp/pg/pgsql08.html)

roadmaps/software-design-architecture/content/transaction-script@tyReIY4iO8kmyc_LPafp1.md

@@ -4,5 +4,5 @@ Transaction Script is a pattern used in enterprise application development that
 
 Visit the following resources to learn more:
 
-- [@article@Transaction Script Pattern](https://gunnarpeipman.com/transaction-script-pattern/)
+- [@article@Transaction Script Pattern](https://martinfowler.com/eaaCatalog/transactionScript.html)
 - [@video@Tutorial - Transaction Script Design Pattern](https://www.youtube.com/watch?v=fnsU9cqcY3I)

roadmaps/system-design/content/tcp@2nF5uC6fYKbf0RFgGNHiP.md

@@ -6,5 +6,5 @@ Visit the following resources to learn more:
 
 - [@opensource@What Is TCP?](https://github.com/donnemartin/system-design-primer#transmission-control-protocol-tcp)
 - [@article@What is the difference between HTTP protocol and TCP protocol?](https://www.quora.com/What-is-the-difference-between-HTTP-protocol-and-TCP-protocol)
-- [@article@Networking for game programming](http://gafferongames.com/networking-for-game-programmers/udp-vs-tcp/)
+- [@article@Networking for game programming](https://gafferongames.com/post/udp_vs_tcp/)
 - [@article@Key differences between TCP and UDP protocols](http://www.cyberciti.biz/faq/key-differences-between-tcp-and-udp-protocols/)

roadmaps/system-design/content/udp@LC5aTmUKNiw9RuSUt3fSE.md

@@ -4,6 +4,6 @@ UDP, or User Datagram Protocol, is a connectionless protocol that sends data wit
 
 Visit the following resources to learn more:
 
-- [@article@Networking for game programming](http://gafferongames.com/networking-for-game-programmers/udp-vs-tcp/)
+- [@article@Networking for game programming](https://gafferongames.com/post/udp_vs_tcp/)
 - [@article@Key differences between TCP and UDP protocols](http://www.cyberciti.biz/faq/key-differences-between-tcp-and-udp-protocols/)
 - [@article@Difference between TCP and UDP](http://stackoverflow.com/questions/5970383/difference-between-tcp-and-udp)

roadmaps/terraform/content/jenkins@qFpaqOSoefTyKxmI-FRZt.md

@@ -5,5 +5,4 @@ Jenkins can orchestrate Terraform workflows using Pipeline scripts written in Gr
 Visit the following resources to learn more:
 
 - [@article@Terraform with Jenkins – How to Manage Workflows](https://spacelift.io/blog/terraform-jenkins)
-- [@article@£article@How to run Terraform in your Jenkins CI/CD pipeline.](https://blog.digger.dev/how-to-run-terraform-in-jenkins/)
 - [@video@How to Use Terraform and Jenkins to Automate Infrastructure Setup](https://www.youtube.com/watch?v=kIDiP3Unj7Y)

roadmaps/ux-design/content/business-model-inspirator@GI06-DbGyJlQXq5Tyi-aH.md

@@ -3,5 +3,3 @@
 A Business Model Inspirator is a tool or method that helps you to generate new or creative ideas for the strategic, operational, and financial aspects of a business. It helps entrepreneurs, startups, and established companies to explore different ways of designing or improving their business models by drawing inspiration from various sources.
 
 Visit the following resources to learn more:
-
-- [@article@Business Model Inspirator](https://businessdesign.org/knowledge-base/business-model-inspirator)