satisfactory: exponential-notation fix and NOTES.txt (6.1.0+upv1.9.10)

Teil von #157 und Teil von #43.

#157: multiplyQuantity turned a bare byte count into exponential notation.
The null-safe fallback helpers pass values through fromYaml, which parses
every number as float64, and Go's "%v" switches float64 to exponential
notation from about 1e6 upwards. A request of 1048576 became
"1.048576e+06" and the render aborted on the suffix check.

Both printf "%v" sites are replaced by the canonical satisfactory.formatNumber
helper: the input of multiplyQuantity and the output of a non-integer product.
The second one never reached the suffix check, so it did not abort - it
rendered a silently invalid quantity that only the API server would reject.

#43: adds templates/NOTES.txt. The chart has no Ingress and no secrets, so
the notes cover what an operator would otherwise read out of the templates:
the NodePort a player actually dials and the pinned-port collision between
two releases, the 20-minute Steam download budget and that SKIPUPDATE is
false on every start, what a green pod does and does not prove (no probe
ever touches the UDP game port), that saves and game files share one PVC on
a hardcoded longhorn class which helm uninstall deletes, the emptyDirs
counting against the ephemeral-storage limit, the deliberate limitFactor 2
and fsGroupChangePolicy OnRootMismatch, and that game.seasonalEvents is
passed through to DISABLESEASONALEVENTS uninverted.

No rendered Kubernetes object changes, so the bump is minor; appVersion
stays v1.9.10.

satisfactory/Chart.yaml

@@ -3,7 +3,7 @@ name: satisfactory
 description: A Helm chart to deploy a Satisfactory Gameserver on Kubernetes
 icon: https://raw.githubusercontent.com/wolveix/satisfactory-server/main/.github/logo.png
 type: application
-version: 6.0.0+upv1.9.10
+version: 6.1.0+upv1.9.10
 appVersion: "v1.9.10"
 maintainers:
   - name: jklein