Add topology foundation and safer Windows helper

[daredoole]

Summary

• add a standalone topology model foundation with machines, displays, directed border links, wrap policy, validation diagnostics, and dry-run edge transitions
• add topology regression tests for AAB, BAA, ABA, stacked, asymmetric resolution scaling, wrap on/off, and validation failures
• harden the generated Windows pairing helper with -DryRun/-Check, schema/version guards, backup-before-write, restore command output, and no destructive process/service management
• add migration and compatibility docs for MWB peer expectations, Linux session caveats, auth sources, clipboard helpers, trusted LAN operation, and topology roadmap

Scope

This is stacked on PR #11 and builds on the current implementation. It does not wire the new topology model into runtime cursor movement yet. Current MWB-compatible behavior remains intact while the new model and tests establish the Phase 2 foundation.

Validation

• cmake -S . -B build
• cmake --build build -j2
• ctest --test-dir build --output-on-failure
• bash -n scripts/inputflow-diagnostics-bundle.sh
• bash -n mwb-desktop-ui.sh
• scripts/validate-rpm-packaging.sh
• git diff --check
• diagnostics bundle smoke test with summary.json validation

[daredoole]

Manual CI run for this stacked PR passed: https://github.com/daredoole/inputflow-linux/actions/runs/25084221577

Jobs passed:

• Ubuntu build and tests
• Fedora build and tests
• ASan and UBSan
• Static checks