fix(routing): research before classifying subagent work

[Phelan164]

Summary

Follow-up to #52. The routing prompt previously treated uncertainty as difficult work, and missing classification metadata automatically selected Astra High. Require bounded research and focused clarification before classification, and assess reviewers independently from the completed diff and risk.

Default uncertain_tier to inherit: unclassified calls receive no model override or routing state. Preserve explicit choices, classified reviewer floors, model mappings, escalation limits, and existing explicitly configured tier fallbacks. Document how existing installations migrate their private policy and preserve custom app adapters.

Validation

• python3 scripts/validate_repo.py
• Playground tests pass when the lab changed — lab unchanged; both tests passed.
• Changed skills pass quick_validate.py — not applicable; no skills changed.
• Version-sensitive product claims link to official documentation — existing references preserved; classification rules are labeled community preferences.

Additional checks:

• Routing tests: 29 passed; regression checks failed against the previous behavior.
• Full utility tests: 78 passed with ResourceWarning treated as an error.
• Living-wiki lint: passed, zero warnings.
• Measurement-template validation, Python compilation, and git diff --check: passed.

Safety and scope

• Examples contain no credentials or destructive defaults.
• Community practices are labeled as such.
• The change is limited to the described scope.

No main-session model, permissions, or model-tier mapping changes. Inheritance leaves native model resolution intact and does not guarantee a cheaper model. Existing private YAML files must opt into uncertain_tier: inherit; existing explicit fallback tiers remain compatible. Local app-adapter changes are outside this PR. Runtime activation and actual child-model selection are not tested by this repository change.

Rollback: revert this PR or retain an explicitly configured fallback tier in the private policy.