chore: prepare v0.1.0 release

[backnotprop]

Summary

• patch fast-uri and qs in the Claude Channel dependency tree
• add contributor guidance and bug and feature issue forms
• replace release-day placeholders with v0.1.0 package and verification instructions
• restore accessible contrast for share popover headings

Verification

• pnpm audit --prod
• Claude Channel typecheck and focused tests
• pnpm check
• pnpm test:web
• AWS and Google Cloud deployment package tests
• object-storage and external-storage runtime tests
• pnpm test:coverage
• local package test
• performance baseline and capacity test
• compact and external-storage Compose tests
• Helm and disposable Kubernetes test
• OIDC integration test

The canonical local gate encountered two unrelated one-off timeouts. Each failed stage passed immediately in isolation, and every remaining gate stage then passed. The release dry run will repeat the canonical gate on clean CI.