docs(webkit): update PROCESS.md CI jobs, base branch and standard counts

[isaque-bock-azion]

Summary

• Stage 5 CI table now matches governance.yml: adds lint-canary, smoke, tests, visual, the TruffleHog / test:gate / doc-standards steps, and the real build commands (pack:check + size).
• Base branch corrected from dev to main (stage table, Stage 5, git-workflow row).
• Standard counts brought to the current 27 (15 general / 12 webkit), adding the missing comments and authoring-docs rows.

How to test

1. Open packages/webkit/docs/PROCESS.md → Stage 5 details; every job in the table matches a job in .github/workflows/governance.yml (and vice versa).
2. Compare the scope tables against .claude/rules/README.md — same 27 rules, same general/webkit split.

Notes

• Docs only — no release.
• .claude/rules/README.md still says git-workflow is "based on dev"; it's a shared rules doc, so it's left for a separate PR.