Go 1.22-compatible grpctransport variant (demand-driven)

[zeevdr]

Description

The grpctransport SDK module requires Go 1.24 because google.golang.org/grpc itself pins that version. This pushes consumers stuck on Go 1.22 to either upgrade their toolchain or use the core SDK (configclient, configwatcher, adminclient) with a custom transport.

If demand warrants it, we'd build a grpctransport-legacy (or similar) module that pins an older grpc version (~v1.60–v1.65 era) compatible with Go 1.22.

Trade-offs of a legacy variant:

• Older grpc = missing ~2 years of bug/security fixes
• Extra module to maintain + test in CI
• Consumers must pick between new features vs. old toolchain

How to signal demand

• React with 👍 if you need this
• Comment with your Go version constraint (why Go 1.22, which grpc features you don't need)

Acceptance criteria

• Gather demand signal (reactions + comments)
• If ≥5 concrete asks: design legacy module, pick pinned grpc version, add CI matrix
• If not: close with note, revisit on next major grpc bump