Shift config of "known-sdks.ts" to SDK-side config file

[chr-hertel]

I really like the idea of easing the options handling and execution of the conformance runner, but immediately fell into the pitfall that this requires cross repo PRs and also decouples the versioning a bit inconvenient if changes are needed.

of course the sdk map would stay in this repo, but after checkout it could check for a conformance.yaml with the relevant settings:

# modelcontextprotocol/go-sdk
# conformance.yaml
build: 'go build -o ./.conformance-server ./conformance/everything-server && go build -o ./.conformance-client ./conformance/everything-client'
client:
    command: './.conformance-client'
server:
    command: './.conformance-server -http=localhost:3000 -stateless=false'
    url: 'http://localhost:3000'
expectedFailures: 'conformance/baseline.yml'
specOverrides:
    '2026-07-28':
        server: { command: './.conformance-server -http=localhost:3000' }

WDYT?