feat(js/ai): added support for dynamically resolvable resources

[pavelgj]

ai.defineResource({
  uri: 'my://resource/{param}',
  description: 'provides my resource',
}, async ({uri}) => {
  return [{ text: `resource ${uri}` }]
});

await ai.generate({
  prompt: [{text: 'analyze this: '}, { resource: { uri: 'my://resource/value' } }]
})

Checklist (if applicable):

• PR title is following https://www.conventionalcommits.org/en/v1.0.0/
• Tested (manually, unit tested, etc.)
• Docs updated (updated docs or a docs bug required)

[mbleigh]

Looking good, few comments and higher-level questions:

1. Will resource resolution show up in traces?
2. Should we put this in beta or go straight to stable?
3. At the moment the action name is the URI but the metadata gets annotated with both the name and the URI - should we either allow an (optional?) name for a resource template or have metadata just be {resource: {uri: "..."}}
4. Should we consider the part type being {resource: {uri: "..."}} instead of {resource: string}? I'm torn, because I like the simplicity a lot but worry if we might add something later...maybe better to keep it simple.

[pavelgj]

Looking good, few comments and higher-level questions:

1. Will resource resolution show up in traces?

Yes:

2. Should we put this in beta or go straight to stable?

I'm fine with stable if you're happy with the API.

3. At the moment the action name is the URI but the metadata gets annotated with both the name and the URI - should we either allow an (optional?) name for a resource template or have metadata just be {resource: {uri: "..."}}

you're talking about generate message metadata (on the part)?
right now it's:

        metadata: {
          resource: {
            name: 'test://resource/{param}',
            uri: 'test://resource/value',
          },
        },

name referring the action name. Action name is derived from either uri or template (whichever one is provided).
The uri in metadata might be misleading... I'm thinking value instead.

        metadata: {
          resource: {
            name: 'test://resource/{param}',
            value: 'test://resource/value',
          },
        },

4. Should we consider the part type being {resource: {uri: "..."}} instead of {resource: string}? I'm torn, because I like the simplicity a lot but worry if we might add something later...maybe better to keep it simple.

yeah... judgement call. It's conceivable that some other options might get added....