fix(spectator): rebuild the overview instead of showing an empty grid

[TheMeinerLP]

Proposed changes

The spectate overview showed no survivors at all, even while survivors were still alive.

Root cause: SpectatorInventory is constructed in the Cygnus constructor at server start, and its register() call builds the inventory and computes the data layout right there, at a point where the survivor team is still empty. The head list was never rebuilt afterwards. Aves' InventoryBuilder#invalidateDataLayout only clears the valid flag while nobody has the inventory open, and the following GlobalInventoryBuilder#getInventory skips the rebuild: it computes applyLayout from the design layout flag, and updateInventory(inventory, locale, false) returns before it ever reaches the retrieveDataLayout branch. So the empty list from server start stayed for the whole round.

Fix: a SpectatorInventory#refresh that invalidates both layouts, called from open and from SpectatorService#updateInventory (which the death and quit listeners already drive). Invalidating the design layout as well is also what clears the inventory. A data layout can only write items: applyDataLayout skips null and air stacks, so a blanked slot is never written back and the head of a player who left the round would otherwise stay in place and stay clickable.

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)

Checklist

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• I have read the CONTRIBUTING.md
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

Two tests come with the fix, both failing on main:

• SpectatorInventoryTest#testOpenPicksUpSurvivorsThatJoinedAfterTheInventoryWasBuilt reproduces the production order, meaning the inventory is built while the team is still empty and survivors join later.
• SpectatorInventoryTest#testOpenDropsHeadsOfPlayersThatLeftTheSurvivorTeam covers the stale head.

The fix stays inside this repo and uses only Aves' public API, so no Aves release is needed. Worth noting that the same limitation would bite any other Aves inventory whose data layout changes while it is closed.

The companion PR on branch fix/spectator-flight-cooldown fixes the spectator flight and stamina bugs. The two touch SpectatorService in different places and merge onto main without a conflict, and both were verified merged together with a green ./gradlew build.

[github-actions]

Test results

  336 files    336 suites   2m 6s ⏱️
  479 tests   473 ✅  6 💤 0 ❌
1 440 runs  1 422 ✅ 18 💤 0 ❌

Results for commit 49704f8.

[theEvilReaper]

This is just a hotfix for the inventory update and does not address the underlying issues.

With this approach, every time a player opens the inventory, all items aligned with the background and data layers are recalculated. A proper fix would be to identify the specific positions where the data layout needs to be invalidated and only recalculate those positions when necessary, rather than triggering a full recalculation on every inventory open.

[theEvilReaper]

See above