feat: add GCP project integration

[h13]

Summary

• Add --gcp-project <NUMBER> option to scripts/init.sh — binds GAS projects to a standard GCP project via clasp create --parentId, includes projectId in CLASP_JSON, and sets GCP_PROJECT_NUMBER as a CI/CD variable
• Add src/setProperties.ts + scripts/set-properties.sh for Script Properties injection via clasp run
• Add auto-injection step in CD workflows (GitHub Actions + GitLab CI) — runs when both GCP_PROJECT_NUMBER and SCRIPT_PROPERTIES are set
• Add post-deploy hook examples (.github/hooks/post-deploy.sh.example, .gitlab/post-deploy.yml.example)
• Update README (EN/JA), setup docs, jest config, and .templatesyncignore

Motivation

• Centralize Cloud Logging / Error Reporting / API usage monitoring across all GAS apps
• Enable clasp run so CI/CD can automatically inject Script Properties (API keys, webhooks, etc.)

Test plan

• pnpm run check passes (lint + typecheck + test)
• init.sh --gcp-project 123456789 creates GAS projects with --parentId
• CLASP_JSON includes projectId field when GCP project is specified
• set-properties.sh --json '{"KEY":"value"}' calls clasp run setScriptProperties
• CD pipeline skips property injection when GCP_PROJECT_NUMBER or SCRIPT_PROPERTIES is not set
• Backward compatible — init.sh without --gcp-project works as before