Execute event pipeline end-to-end

Upgrade timeline civilization events end-to-end

When batch-upgrading timeline events with photos and verification across multiple gates.

• · args: JSON object or string with phase configuration

• · JSON object matching declared schema

• · Claude Code Workflow harness (injected globals: agent, parallel, phase, log)
• · Local filesystem + shell scripts

• · Workflow harness must inject phase(), agent(), parallel() globals
• · args must be a valid plain object (not a string) before phase execution

• · Phase exits early if any agent returns null or throws
• · Subsequent phases cannot recover from prior phase failure