Fix swap_source.sh: p4 status was flagging the .current-source marker file (and, for sdp, the new .p4ignore.local itself) as untracked, which broke test_preflight.sh/uat -- caught during the first real bootstrap run on the r9x86_64 canary.
Fix: chain a local-only .p4ignore.local onto P4IGNORE via P4's semicolon-list syntax (excluding both .current-source and itself) rather than bin's previous approach of replacing P4IGNORE outright, which had been silently discarding the repo's own real .p4ignore patterns. Unifies bin/sdp handling (both now sync -f .p4ignore + chain .p4ignore.local).
Agent: Claude Code, Model: Claude Sonnet 5 (claude-sonnet-5), operating as bot_Claude_Anthropic.