[design] Make GA API plan

[BigLep]

Done Criteria

We're doing an “architectural lens” pass with on what Synapse SDK looks like to external developers to decide what the “public, stable surface” is for GA. #483 (or a linked issue) has been updated with the scope of the changes we're going to make to the Synapse API for GA.

Why Important

See #483

Notes

• We have to be pragmatic and go after the "must-dos" or "lower effort / higher impact" items. This isn't a "boil the ocean" endeavor.
• Related issues where API improvements have been discussed:

[BigLep]

@hugomrdias : @rvagg and I were talking and we were thinking would be a great item for you to own/drive if possible (i.e., get the design in place with collaboration with Rod even if others come in and do some of the work).

[BigLep]

It's TBD where we'll be posting the "design" for the API changes (maybe it'll just be the issue?), but if anyone has input or suggestions they want to share in the interim, feel free to add comments to this issue...

[BigLep]

Assigning to @hugomrdias as it sounds like per conversation with @rvagg that he'll take this.

[rvagg]

@hugomrdias part of this was your "everything takes an object". We either need to lump that into here or split it out as a separate issue to track.

[BigLep]

2025-12-17 conversation: will create the design as part of doing #272

[hugomrdias]

can i take over the OP to list out items for discussion ?

so i dont forget

• number to bigint
• method options as objects
• remove runtime address fetch from FWSS now that we have build time fetch on generate:abis script
• more will come