env: template catches up with the v3 engine

.env.template still shipped the deleted external-orchestrator line
(REBASE_ORCHESTRATOR_CMD, retired in the 012e900 cutover) and never
mentioned the variables the v3 remote-CI path actually reads:
GITHUB_TOKEN (header-auth push), BUILDKITE_API_TOKEN (provider client,
write_builds), REBASE_CI_TIMEOUT_SEC (per-build monitor budget), and
the VLLM_OMNI_VENV path fallback the manifest expands for the target
venv. REBASE_AGENT_ROOT stays as the optional read-only parent
knowledge-store pointer.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CD4ifoCtkdQXxEyfCPyzLV

Author: tzhouam

.env.template

@@ -87,14 +87,23 @@ MCP_REPO_ALLOWLIST=["vllm-omni", "afd-plugin"]
 # committed manifest stays portable. REPO_PATHS above takes precedence.
 VLLM_OMNI_REPO=/path/to/vllm-omni
 VLLM_UPSTREAM_REPO=/path/to/vllm
+VLLM_OMNI_VENV=/path/to/vllm-omni-venv
 AFD_PLUGIN_REPO=/path/to/afd-plugin
 
 # Push safety: pushes are dry-run unless this is 1
 ALLOW_PUSH=0
 
-# External locked rebase pipeline (adapter zero delegates to it)
+# repo-rebase-v3 remote CI (rebase_mode=remote_ci/full): pushes authenticate
+# with GITHUB_TOKEN (header auth; no credential helper is consulted) and the
+# Buildkite provider client needs BUILDKITE_API_TOKEN (write_builds scope).
+# REBASE_CI_TIMEOUT_SEC bounds the per-build monitor (default 10800 = 3h;
+# raise it when the pipeline's agent queue is slow).
+GITHUB_TOKEN=
+BUILDKITE_API_TOKEN=
+# REBASE_CI_TIMEOUT_SEC=18000
+
+# Parent-agent knowledge stores (read-only compat layers; optional)
 # REBASE_AGENT_ROOT=/path/to/vllm-omni-rebase-agent
-REBASE_ORCHESTRATOR_CMD=omni-rebase-orchestrator --dry-run
 
 # Escalation email (optional; Resend first, SMTP fallback)
 NOTIFY_EMAIL=