Make FactRetrieverContext generic to support context extension

[kurtaking]

Hey, I just made a Pull Request!

Previously, the Tech Insights plugin only supported a fixed set of services in the FactRetrieverContext. This change enables plugin consumers to pass additional custom services into their FactRetriever implementations without modifying the core plugin code, improving extensibility while preserving the plugin's API contract.

• update FactRetrieverContext to accept a generic extension type
• make FactRetriever interface generic to work with extended context types
• update FactRetrieverRegistration and FactRetrieverRegistry to support generic typing

Example

type MyCustomFactRetrieverContext = FactRetrieverContext<{
  customService: MyCustomService;
}>;

handler: async ({ discovery, entityFilter, auth, ..., customService }: MyCustomFactRetrieverContext) => {
   ....

   const somethingCustom = customService.doSomething()
   ...   
}

Alternative

We wrap the creation of the FactRetriever with a factory function that takes our internal serviceRefs.

✔️ Checklist

• A changeset describing the change and affected packages. (more info)
• Added or updated documentation
• Tests for new functionality and regression tests for bug fixes
• Screenshots attached (for UI changes)
• All your commits have a Signed-off-by line in the message. (more info)

[backstage-goalie]

Changed Packages

Package Name	Package Path	Changeset Bump	Current Version
@backstage-community/plugin-tech-insights-node	workspaces/tech-insights/plugins/tech-insights-node	minor	v2.3.0

[kurtaking]

@punkle @Xantier - can I get your input here? Thanks!

[Xantier]

@kurtaking Looks straightforward, what kind of questions did you have around this?

[kurtaking]

@kurtaking Looks straightforward, what kind of questions did you have around this?

Hey @Xantier, sorry, should have been a bit more specific. I am looking for a review 😁

It feels weird to merge without a +1 from plugin owner unless y'all are okay with merging based on a +1 from any community maintainer.