first-officer: add Step 5 output-validation gate to Completion and Gates

[iamcxa]

Problem

The FO advances entities through the pipeline based on ## Stage Report existence alone, without validating that the completed stage produced its expected ## {Stage_Name} Output section. When a worker hits its checklist but fails to write the Output section (context pressure, early-exit paths, circuit breakers), the entity silently advances to the next stage with no usable output. Downstream stages then discover the missing input and return BLOCKED — but the entity status has already moved forward, leaving it stranded mid-pipeline.

Fix

Add Step 5 to the Completion and Gates flow in first-officer-shared-core.md:

• For every non-initial, non-terminal stage with a skill: property, grep the entity file for ## {Stage_Name} Output before advancing
• Missing/empty Output → re-dispatch the same worker once with a pointed instruction to write the missing sections
• Second failure → escalate to captain with a visible diagnostic, halt advancement
• Skip the check for stages without skill: (draft, done)

Evidence

The bug was observed on a ship-flow workflow (spacedock-ui project) where three entities advanced past their stages without corresponding Output sections:

• Entity 035 war-room-scroll-fix — status: plan, no ## Plan Output
• Entity 038 design-system-v2 — status: execute, no ## Plan Output
• Entity 029 upstream-contributions-scan — status: verify, no ## Plan Output

Paired fix on the skill side (each stage skill mandates writing Output before early-exit) lives in the downstream workflow repo (spacedock-ui). This FO change is the generic backstop that applies to every spacedock-commissioned workflow.

Convention

Follows the entity-body-schema convention: "Each stage writes up to 3 standard blocks: Output, Report, UAT with headers ## {Stage} {Block}."

Testing

• make test-static passes: 454 passed, 22 deselected, 10 subtests passed in 24.56s
• Touches only skills/first-officer/references/first-officer-shared-core.md (+8 lines)
• No runtime adapter changes needed — both claude-first-officer-runtime.md and codex-first-officer-runtime.md describe HOW to detect worker completion (Agent(), wait_agent) but don't duplicate the Step 1-4 checklist prose, so Step 5 addition to the shared core is sufficient.

Stats

• 1 commit
• 1 file changed
• 8 insertions, 0 deletions

[clkao]

I am curious why limit the stage output verification only when skill is defined?