- `_applyResearchEffects` now receives the node id explicitly instead of
reading `node.id`, which is undefined (the id is the key in the tree's
`nodes` map, not a field on the object) — this was silently skipping
`activateGates` so researched jumpgates stayed dark
- Add `systemIdOfGatesNode()` as the pure inverse of `systemNodeId()` for
the gates node, with round-trip tests
- Reconcile gate activation in `_onEnterSystem()`: if the gates tech is
already unlocked, re-run `_activateSystemJumpgates` (idempotent) so a
missed activation self-heals on the next entry/jump/reload
- Make `_activateSystemJumpgates` idempotent by tracking fresh keys and
early-returning when everything is already online
- Add `navPoints()` and `navChart()` to SystemCategory.js as pure,
testable cores for the jumpgate unlock condition (discovered/missing
split over all NAV points)
- Add `js/dev/NavDiag.js` with `orbitNav()` / `orbitNavBrief()` console
commands that print the live NAV chart and which objects are still
undiscovered, installed by `main.js` on every page load
- Update `data/landing.json` to reference the correct gasgiant surface/shop
videos for slot 03
- Add tests for `navPoints`, `navChart`, and `systemIdOfGatesNode`
- Document the activation wiring bug, the `orbitNav()` diagnostic, and the
new pure functions in PROJECT_NOTES.md
