Add blog section for tutorials and announcements

[AmitoVrito]

Description

Enable Docusaurus blog plugin.

What to do

• Create first posts: 'Introducing SynapseKit v0.5.0', 'Why we built SynapseKit', 'Building your first RAG pipeline'
• Add blog link to navbar
• Configure RSS feed

[AmitoVrito]

Thanks for your interest! I will assign it to you. Before you start, could you give the repo a ⭐ on the main repo (https://github.com/SynapseKit/SynapseKit)? It really helps with visibility for a new project. Looking forward to your PR!

[AmitoVrito]

Done — blog enabled in docusaurus.config.ts + v1.2.0 release post added in PR #44.