DirXMLDevWeb 0.79.0

Needs DirXMLDev 0.55.0.

Added

• Compare projects: pairing on the page. Pair with … proposes the map (look-alike
  drivers, the nearest-named servers) or shows the pair's file, compares with it as you edit it,
  and lets you leave differences pending or accept them as known. Then it writes the map (as
  written), the first record and the known differences into a new branch, promote/<project>-pair-<time>,
  committed and pushed for review. GET /api/promote/map, POST /api/promote/pair,
  GET /api/promote/compare?map=.
• Known differences on the page: accept a difference as known (intended, or to decide later),
  or a known one as no longer known. The decisions go with the next promotion, or alone in a
  branch of their own (known, forget on POST /api/promote/apply).
• Cases move with their driver: when both projects have simulator cases, their files compare
  and promote as cases/<path>, with driver= written as this project names the driver.
• Agents: MCP compare_projects (each difference with its bucket and changed lines) and
  promote_changes (dry run by default; the branch otherwise). GET /api/promote/compare?brief=true,
  dryRun on POST /api/promote/apply.
• Docs: compare-projects.md (pairing, known differences, cases, agents, a first time
  through), agents.md (the two tools), the tutorial's next steps. git-workflow.md opens with the
  two ways to keep environments side by side, and when to choose which. features.md lists
  Compare projects.