[ElephantGit]

Agent prompts now resolve variable templates before dispatch, and successful session settlement publishes the initial turn's final complete assistant message as the node's output root. Named Output bindings and the linked IssueRun message can therefore carry the actual answer. Session evidence is stored separately in sessionEndReason; terminal historical runs are not backfilled.

The implementation reads durable assembled history for the current node attempt and initial turn, excludes failed/cancelled or unrelated turns, preserves committed output when the run is cancelled, and rejects truncated history. First dispatch and retry use the scoped variable pool used by conditions, including loop/iteration inputs.

Rebased onto main a4dfee1 after #179 merged. Compared with the previously validated b327040 candidate, this retains main's Output upgrade-compatibility documentation, container failure policy, state-budget enforcement, and timeout drain barriers. An additional fix keeps drain diagnostics in sessionEndReason instead of Agent output roots and preserves Agent failure diagnostics in run-level errors. Loop/iteration timeout tests now assert that both live and archived states have no output root. This PR adds no migrations.

Validation: PostgreSQL-backed workflow regressions, the full Go race suite, formatting, Go lint (0 issues), and OpenAPI regeneration consistency passed locally. All new-head CI checks passed: frontend, packages, four integration shards, and the final complete/disjoint coverage aggregate. CI proto lint, breaking-change detection and generation drift checks passed (local generation could not reach the remote plugin service). The frontend generated-client diff remains comments only.

ADR: implements the existing variable-root and execution-context obligations in specs/decisions/cloud/workflow/0-cloud-side-scheduler-owns-workflow-execution.md, whose status remains implemented. It adds no architectural decision and preserves the approved loop/iteration ownership and cancellation semantics. A separate specs follow-up under the parent task will remove the known-gap note and synchronize core-case evidence after review and acceptance; this PR does not prematurely change that evidence.

Real-model acceptance passed for b327040 before this rebase. That result is not acceptance of the new head. Full post-merge main acceptance remains assigned to the existing follow-up.

Refs ora-space/circus#676

[EricWvi]

owner review: 模板渲染、最终回答写入与 sessionEndReason 分离核对通过。