Replace agent orchestration cruft with project-local skills

[jonbaldie]

Summary

• replace Beads tracking guidance with GitHub Issues, default triage labels, and single-context domain docs
• remove Gastown handoff/done commands, Beads hooks/config references, Dolt ignores, and the generated Stryker sandbox snapshot
• preserve Claude and Serena as integral project tooling, retain Serena TypeScript configuration, and add the requested Serena guidance to AGENTS.md
• install all 41 current mattpocock/skills project-locally with skills-lock.json
• adapt copied skill guidance to enforce this repository no-mocks policy

Validation

• Deno 2.7.6
• CircleCI compile command: pass
• CircleCI test command: 177 passed, 0 failed
• deno check main.ts: pass
• live HTTP health/enqueue/dequeue smoke: pass with graceful shutdown
• skill manifest/lock integrity: 41 of 41 pass
• two-axis review: 0 standards findings, 0 spec findings

Existing baseline

Repository-wide deno fmt --check and deno lint remain red on pre-existing untouched source/test findings; CircleCI does not run those gates.