Barslev/add reach concurrency and reach disable analysis splitting

[barslev]

Adds options --reach-concurrency <number> and --reach-disable-analysis-splitting for socket scan create --reach.

---

Note

Adds --reach-concurrency and --reach-disable-analysis-splitting flags, plumbs them through create/reach commands to Coana, updates defaults, help, tests, and bumps version.

• Reachability flags
  • Add --reach-concurrency <number> and --reach-disable-analysis-splitting in reachability-flags.mts (defaults: 1 and false).
• Commands
  • socket scan create --reach: parse/validate/pass new flags in cmd-scan-create.mts.
  • socket scan reach: parse/pass new flags in cmd-scan-reach.mts.
  • CI/GitHub flows: set defaults in ci/handle-ci.mts and create-scan-from-github.mts.
• Execution
  • Wire to Coana in perform-reachability-analysis.mts as --concurrency and --disable-analysis-splitting.
• UX/Docs/Tests
  • Update help text; extend tests in cmd-scan-reach.test.mts.
  • Bump version to 1.1.29; update CHANGELOG.md.

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