feat: audit cross-provider place conflicts

[atomantic]

Automated PR created by PortOS Chief of Staff.

Summary

Improved the existing tree auditor to surface real cross-provider vital-place conflicts without creating alias or detail-loss noise.

Changes

• Added a shared cross-source mismatch matcher, used by both date and new place audit checks.
• Enabled normalized place mismatch auditing by default and added unit coverage for conflicts and false-positive guards.
• Updated the roadmap and unreleased changelog; committed as c55df0b.
• Validation passed: focused Vitest suite (26 tests), full production build, and git diff --check.
• Assumption: the assigned worktree is SparseTree (no data/COS-GOALS.md exists), so its GOALS.md, DONE.md, and PLAN.md supplied the feature-review evidence.

[atomantic]

Review loop blocked before merge.

• Codex (gpt-5.6-terra): completed three rounds; two substantive cache-path defects were fixed and the final pass returned no further findings.
• Ollama (pinned hf.co/empero-ai/Qwythos-9B-Claude-Mythos-5-1M-GGUF:BF16): both allowed attempts failed with curl: (52) Empty reply from server; the local reviewer endpoint returned no .findings verdict.

Validation after the fixes: npm run test:unit (116 passing) and npm run build (shared, server, and client) passed. The PR is intentionally left open because the required Ollama review was a hard error, not a clean/capped verdict.