feat(#385): rename Knowledge Store back to Knowledge Base across new KB server and integrations

[NoveliaYuki]

Purpose

Rename "Knowledge Store" / "knowledge store" back to "Knowledge Base" / "knowledge base" across the new lamb-kb-server service and all the code that references it (LAMB backend Creator Interface, CLI, frontend, database column / table names where applicable).

The "Knowledge Store" name was a transient artefact: it was adopted only while the legacy server (lamb-kb-server-stable) and the new server coexisted in the same codebase, so source-level references and route paths to the two services would not be ambiguous. With the legacy server now on its documented deprecation path and no new knowledge bases being created against it, the new server should reclaim the domain-natural name. The thesis already adopts the target terminology (Knowledge Base) ahead of the code rename to avoid having to revise the document once the codebase catches up.

Related to (but independent from) #384.

Acceptance criteria

• Rename the lamb-kb-server service references in user-facing docs and CLAUDE.md from "Knowledge Store" to "Knowledge Base"
• Rename code-level identifiers where they leak through to API surfaces or user-visible text:
  • HTTP route group /creator/knowledge-stores/* → /creator/knowledge-bases/* (with backward-compatible alias for at least one release if existing assistants are bound to old paths)
  • LAMB backend modules knowledge_store_router.py, knowledge_store_client.py, knowledge_store_rag.py → knowledge_base_*
  • LAMB database tables knowledge_stores, kb_content_links reviewed for naming (keep kb_* short form where it already reads as "knowledge base")
  • CLI command group lamb ks / lamb knowledge-store → lamb kb / lamb knowledge-base, with the old names kept as aliases for one release
  • Svelte frontend route /knowledge-stores → /knowledge-bases (the existing redirect into the Sources of Knowledge hub stays)
  • Frontend component directory frontend/svelte-app/src/lib/components/knowledgeStores/ → knowledgeBases/
  • i18n keys knowledgeStores.* → knowledgeBases.* (with deprecation period)
• Update CLAUDE.md to drop the legacy-server-versus-new-server naming disambiguation that the old name was added to enforce
• Update the README of lamb-kb-server
• Update test names and test descriptions
• Coordinate the rollout with the LAMB backend and frontend so HTTP/URL aliases overlap by at least one release
• Do not start until the legacy lamb-kb-server-stable deprecation status is confirmed with the contributors (the rename relies on the disambiguation no longer being necessary)

Author: @NoveliaYuki

[granludo]

ok, but have we decided to remove the old one or are we going to maintaing both for backward compatibility ....
the issue here is MIGRATION , we have kbs in production and we can't break them

[NoveliaYuki]

Even if we maintain backward compatibility or migrate, it will be only for a temporary time. Sooner or later the old kb server will be deprecated and that's when the rename will happen, after the old one gets deprecated there will only be one kb server left.