Add issuePrefix/issueCounter to companies and issueNumber/identifier to issues
for human-readable issue IDs (e.g. PAP-42). Add runId to activity_log for
linking activity to heartbeat runs. Rework DB client to support migration
state inspection and interactive pending migration prompts at startup.
Add reopen option to issue comments validator.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
