D111 — Repository E2E tests are deterministic and model-free

Decision. Remove the four OpenCode/LLM-driven scenarios and their agent/sandbox helpers. Keep the six operator scenarios as the repository's end-to-end suite because they deterministically exercise client configuration, provisioning drift, git synchronization/conflicts and scoped authorization through the compiled binary. Run that suite and the HTTP smoke test in CI.

Model interpretation and provider quality are evaluated in real usage, not as a required repository check. test/e2e/ now means protocol/process end-to-end, not "an LLM agent performed the task".

Rationale. The LLM scenarios required an external endpoint, were never executed by GitHub Actions and had no committed maintenance after the initial public release. Their outcome depended on model availability and behavior. The operator scenarios require no credentials and cover cross-component boundaries that isolated Go tests do not.

Consequences. make e2e is deterministic and mandatory in CI; make e2e-quick and the model-related environment variables are removed. The HTTP smoke script moves from the otherwise-empty scripts/ directory to test/smoke/. The obsolete make migrate target is removed because its referenced script no longer exists and wiki migration is provided by cartographer import.