fix(lead): make delegation and acceptance defaults explicit (0.7.3)

[keli-wen]

Summary

With agy:lead, the host could delegate history research while continuing substantial local investigation before the worker returned. The existing guidance allowed that split, leaving users to repeatedly steer delegation and waiting.

Define a general default for research, implementation, review, and writing: orient enough to frame an assignment, delegate coherent substantive work, wait, assess the result, then follow up, take over, or deliver. Require task-appropriate artifacts and evidence for acceptance. Preserve direct handling of small or already-understood work, useful independent host work during waits, and focused verification after results arrive.

Keep context transfer, specialist selection, shared decisions, parallel-edit worktree isolation, and the existing jobs lifecycle explicit. Update the English and Chinese README descriptions and regenerate the Pi skill. Align package, Claude Code, and Codex versions at 0.7.3 and add docs/releases/v0.7.3.md for the release. No companion runtime changes.

Validation

• Full offline suite during implementation: npm test — 195 passed, 0 failed. Final prose revisions were rechecked with the focused checks below.
• npm run check:pi — 11 generated files current.
• node --test tests/pi-packaging.test.mjs — 7 passed, 0 failed.
• git diff --check — passed.
• Skill Creator validation passes for the generated Pi skill. Its generic validator rejects the canonical skill's existing argument-hint field identically on origin/master and this branch; that compatibility limitation is unchanged.
• An independent agent exercised six decision scenarios: discussion research, implementation with PR delivery, an unsupported clean review, a one-line typo, an unsettled API shared by two clients, and independent work during a running investigation. All selected the expected actions. This was a decision simulation, not a live end-to-end orchestration evaluation.