SDK: Add managed hosting credentials and remote workspace callbacks

[C0deKing]

Summary

Project the experimental managed-hosting contract into all six SDKs and add a Go per-host refreshable credential provider. This draft is based on the exact go/v1.0.19 SDK snapshot (f0b503aae1ba151d29d117088de4238d1983e33e, CLI 1.0.95), not current main.

• Add typed hosting kind, runtime principal, and opaque credential-provider registration.
• Preserve ordinary user-local defaults and existing session creation/resume/permission callbacks.
• Keep Go credential registrations isolated per host and release them on startup failure, exit, and disconnect; provider errors do not select ambient authentication.
• Preserve Java's shipped two- and three-argument environment constructors through the generator.
• Generate all six projections from the companion native schema, without hand-editing generated files.
• Add explicit host-only unknown-expiry credentials through GitHubTokenUnknownExpiryResult(&GitHubTokenUnknownExpiry{AccessToken: bearer}). Omit unavailable lifetime metadata without inventing a TTL; reject unknown lifetime for ordinary session providers, including before session ID assignment.
• Retain known hosting lifetime of at least 120 seconds, normal session lifetime greater than one hour, bounded native refresh, and owner/policy validation. Explicit zero/null/invalid lifetime never becomes an unknown-lifetime fallback.

Validation

Workspace increment (91cdf52ec658a22200de6037eea1368137041660):

Use this revision rather than the first workspace snapshot: both copy and move now preserve optional FailIfExists, with regression cases for omitted, true and false values. The expected module version is v1.0.20-0.20261012015351-91cdf52ec658; module acquisition has not been rerun during the download pause.

• Add explicit AhpHostOptions.WorkspaceProvider with typed pre-session Describe/Resolve and guarded Read, Write, Stat, List, Copy, Move, Delete, Mkdir, and Access callbacks. This is separate from durable SessionFS.
• Preserve original AHP parameters, channel, metadata, request identity, int64 offsets, etags and create-only flags. The trusted provider must enforce physical boundaries and write preconditions on hands at execution, not merely during resolution.
• Bound callbacks to eight concurrent invocations per host and a 25-second deadline. Provider errors/disconnects never fall back to brain-local IO; missing operations report NotImplemented. Normal local hosts are unchanged.
• All six maintained SDK generators completed successfully from the native schema artifact emitted by run 38189988952 at 8a3c7fce40d7c4041589a71562ee021b64969667; subsequent native changes did not alter the schema source.
• gofmt -l src/sdk/go/host_workspace.go src/sdk/go/host_workspace_test.go src/sdk/go/host.go src/sdk/go/client.go src/sdk/go/github_token_provider.go: passed (no output) in canonical source.
• TMPDIR=<owned-build-work> MAVEN_OPTS=-Djava.io.tmpdir=<owned-build-work> ./mvnw -o -q -pl sdk spotless:apply: passed.
• git diff --check: passed. All 23 projected source files were verified byte-for-byte against the canonical native SDK.
• New Go workspace tests: passed in complete Linux Go job 114640833947, including pre-session discovery, exact int64/write conditions, copy/move flags, diagnostics isolation, host isolation and cancellation. go test -v ./... -race -timeout=20m and both in-process smoke commands passed; the whole Linux job, including docs checks, succeeded. Complete six-language/platform matrix remains in progress. Replacement existing SDK CI run 38195456927 has passed schema freshness, real Linux native runtime smoke, Go formatting, golangci-lint, and sample go test ./...; full Go subprocess and in-process tests have also passed in job 114640833947; remaining language/platform jobs continue in the same run. Run 38193802110 failed before language tests because its native runtime omitted the engine-owned host.workspace registry entry; the native companion now repairs it. The earlier 38192998800 run predates the move-field repair and is not final-head evidence. Local compilation/downloads remain paused after the shared-disk emergency; no dependency installation was performed.
• Compatible native source 3689ef92 now passes all 149 native Rust targets and real SDK runtime startup smoke. Replacement native artifact is available remotely, expires 2026-10-13 02:33:25 UTC, and was not downloaded during the disk pause. Do not use withdrawn artifact 11722308385. Combined MC/Aspire/browser/inference and live AHP workspace IO are not claimed; the previous unknown-expiry binary still rejects workspaceProvider.

Current unknown-expiry update (b69c6fc1e09d3a03a2790f907fd19927ef3b20a8):

• go test -race ./... -run 'TestAhp|TestGitHubToken|Test.*InstallationConfirmation' -count=1: passed in canonical and projected SDKs.
• npm run typecheck: passed in the canonical Node SDK.
• dotnet build src/GitHub.Copilot.SDK.csproj --no-restore --nologo --verbosity quiet -p:CopilotSkipCliDownload=true: passed, zero warnings/errors.
• ./mvnw -o -q -pl sdk spotless:apply: passed in both SDKs.
• All six maintained generators completed; all 14 changed/new SDK files match the canonical projection byte-for-byte.
• go mod download -json github.com/github/copilot-sdk/go@v1.0.20-0.20261011230559-b69c6fc1e09d: passed without local replaces.
• COPILOT_RUNTIME_HOST_E2E=1 COPILOT_CLI_PATH=<compatible native wrapper> go test -race . -run '^TestAhpHostRuntimeUnknownExpiryOwnerAdmission$' -count=1 -v: passed all four cases against the updated source-built native artifact. Both unknown and known expiry reach unchanged loopback owner denial; explicit zero and cancellation fail before owner lookup. This is negative owner-admission coverage, not successful hosting.
• A standalone go run . <compatible native wrapper> <owned-state-directory> smoke passed using the published module without local replaces: local namespaced host start/list/dispose, managed callback cancellation, and client shutdown. No real control-plane registration or inference was attempted.
• The same native owner-admission test demonstrated the expected unknown-expiry regression against the earlier source-built runtime; the other three cases passed there.
• Rust SDK tests and full SDK/platform/browser matrix: not rerun for this update. The unchanged CLI pin does not implement unknown expiry.

Previous managed-hosting foundation:

• go test ./... -run 'TestAhp|TestGitHubToken' -count=1: passed in the canonical SDK source.
• go test -race . -run 'TestAhp|TestGitHubToken' -count=1: passed in both canonical and projected Go SDKs.
• TypeScript maintained build (node --import tsx esbuild-copilotsdk-nodejs.ts, with declared binaries on PATH) and npm run typecheck: passed.
• Java generator's node --import tsx --test java.test.ts: passed, 49 tests.
• ./mvnw -pl sdk spotless:apply: passed.
• dotnet build src/GitHub.Copilot.SDK.csproj --no-restore --nologo --verbosity quiet -p:CopilotSkipCliDownload=true: passed, compile-only, zero warnings/errors.
• Python generated ordinary/managed hosting option round trips: passed.
• cargo check --no-default-features --features local-runtime,test-support --tests: passed.
• cargo test --no-default-features --features local-runtime,test-support --lib ahp_host::tests::: passed, 49 tests.
• Six language projections: generated successfully with the maintained generators.
• Published Go module github.com/github/copilot-sdk/go v1.0.20-0.20261011215256-1c553e0c8d78: downloaded and verified without local replaces. This is historical unknown-expiry evidence, not a consumer download of the final workspace revision. Current workspace SDK: 91cdf52ec658a22200de6037eea1368137041660 (expected Go version v1.0.20-0.20261012015351-91cdf52ec658); no local absolute replaces. Further local downloads are paused for shared-disk capacity.
• Full platform/runtime/E2E matrix: not run. A compatible source-built native artifact was obtained and exercised for the earlier managed-hosting contract; it predates unknown expiry. The unchanged released CLI pin does not contain this new runtime contract.

Known integration blockers

This is an experimental companion contract, not a completed remote-worker integration. The Go ergonomic provider and six generated wire projections are published; the replacement native artifact and full native tests are available. The complete SDK language/platform matrix and live integration validation are still pending. Repository materialization and physical guard enforcement belong to the authorized hands adapter. Watchers, local terminals, worktree/Git-truth operations and unsupported project mutations return NotImplemented; there is no local fallback.

Native session repository-policy/context discovery remains separate: explicitly supplied allowedModels still performs local policy discovery, and trustWorkingDirectory is rejected with RPC SessionFS. Do not drop those settings or enable local model tools to bypass the limitation. Host-scoped workspace IO does not redirect session inference tools or instructions.

Hosting token refresh does not refresh session inference credentials; ordinary session providers still require a known lifetime greater than one hour. GitHubTokenProviderArgs.Host is verbatim runtime configuration (default https://github.com), not SDK-normalized. Validate it against the intended GitHub origin.

Unattended organization-principal admission remains unsupported. Installation credentials alone do not grant native remote-control entitlement. No owner wire field, tenant-authorization relaxation, production rollout, or new MC public API is introduced.