EPIC: v0.9.0 WhaleFlow branch/leaf workflow mode (tracker, replaces deleted #2667)

[Hmbown]

This re-establishes the v0.9.0 primary tracker; the original EPIC #2667 was deleted (API returns 410) while the milestone description still pointed at it.

Where the foundation actually stands (audited 2026-06-09)

crates/whaleflow is real — ~5.2k lines: typed Workflow IR, Starlark authoring layer, deterministic replay, TraceStore with migrations + parity tests. But execution is a MockWorkflowExecutor, no crate depends on codewhale-whaleflow yet, and the teacher/promotion loop, overlay, and janitor exist only as design. Roughly 60% of the milestone description was unimplemented with zero open tracking issues until tonight.

Remaining workstreams

• whaleflow: real async executor — replace MockWorkflowExecutor #2973 — real async executor (replace MockWorkflowExecutor)
• whaleflow: wire codewhale-whaleflow into tui/cli (currently zero dependents) #2974 — wire codewhale-whaleflow into tui/cli (zero dependents today)
• whaleflow: ARMH/RLM shared-memo integration with live engine + telemetry #2975 — ARMH/RLM shared-memo integration + telemetry
• whaleflow: TeacherReview → StudentReplay → PromotionGate end-to-end #2976 — TeacherReview → StudentReplay → PromotionGate end-to-end
• whaleflow: cached-main overlay #2977 — cached-main overlay
• whaleflow: janitor — stale invalidation, memo cleanup, demotion, trace compaction #2978 — janitor
• whaleflow: TUI /workflows monitoring surfaces — run/inspect/replay #2979 — TUI /workflows monitoring surfaces (run/inspect/replay)
• whaleflow: CI — run workflows/rlm_cache_change.star against mock provider #2980 — CI: workflows/rlm_cache_change.star against mock provider (first definition-of-done item)
• HarmonyOS/OpenHarmony tier-2 target: CI cargo-check job + remaining sandbox/clipboard gating #2970 — HarmonyOS/OpenHarmony tier-2 CI job
• [feat] Run Trace Export System for WhaleFlow/Model Lab #2752 — Run Trace Export for WhaleFlow/Model Lab

Suggested sequencing

1. whaleflow: real async executor — replace MockWorkflowExecutor #2973 + whaleflow: wire codewhale-whaleflow into tui/cli (currently zero dependents) #2974 (make it runnable end-to-end with mock provider), then whaleflow: CI — run workflows/rlm_cache_change.star against mock provider #2980 locks it in CI
2. HarnessPosture v0.9.0 HarnessPosture: model-specific context and subagent policy #2693 + cache-maximalism consolidation (provider-abstraction leg)
3. whaleflow: ARMH/RLM shared-memo integration with live engine + telemetry #2975, then the teacher/promotion loop whaleflow: TeacherReview → StudentReplay → PromotionGate end-to-end #2976 → whaleflow: cached-main overlay #2977 → whaleflow: janitor — stale invalidation, memo cleanup, demotion, trace compaction #2978
4. whaleflow: TUI /workflows monitoring surfaces — run/inspect/replay #2979 monitoring surfaces as the engine stabilizes

Scope, non-goals, definition of done, and release gate: per the milestone description — unchanged by this re-filing.