feat: integrate vector store into configuration and distribution chain

[zhenghaoz]

• Add VectorStore and VectorTablePrefix to DatabaseConfig
• Initialize VectorStore in Master and register gRPC service
• Add VectorStore support in Worker
• Add VectorStore support in Server (RestServer)
• Add NoDatabase type for vectors package
• Add design document

Phases completed:

• Phase 1: Configuration support
• Phase 2: Master integration
• Phase 3: Worker integration
• Phase 4: Server integration

[codecov]

Codecov Report

❌ Patch coverage is 29.41176% with 36 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.31%. Comparing base (36d6e19) to head (a8ce535).
⚠️ Report is 14 commits behind head on master.

Files with missing lines	Patch %	Lines
server/server.go	0.00%	16 Missing and 1 partial ⚠️
worker/worker.go	0.00%	10 Missing and 1 partial ⚠️
master/master.go	0.00%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1220      +/-   ##
==========================================
+ Coverage   72.94%   73.31%   +0.37%     
==========================================
  Files          89       90       +1     
  Lines       16569    16664      +95     
==========================================
+ Hits        12086    12217     +131     
+ Misses       3244     3234      -10     
+ Partials     1239     1213      -26     

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