Streamline adaptive agent orchestration

[CBannink]

Summary

• streamline the primary orchestrator around adaptive INLINE, STANDARD, and DEEP playbooks
• reduce all agent returns to Result, Evidence, and optional Next while adding focused read-only wiki use
• harden OpenCode/Codex installation, migration, configuration preservation, and UTF-8 BOM handling
• refresh README guidance and all 212 generated host adapters

Verification

• npm run typecheck --prefix cli
• npm test --prefix cli (82 tests)
• npm run validate --prefix cli
• npm run check:drift --prefix cli
• git diff --check origin/main...HEAD
• independent staged-diff review: PASS

Notes

• optional local benchmark experiments are intentionally excluded from this PR
• normal work does not modify .wiki