feat(setup): create lobby portals from in-game commands

[TheMeinerLP]

Summary

The setup server gets /setup portal so the build team can create the lobby portals from #326 in-game instead of writing JSON by hand.

• Per-player drafts; nothing is written except by an explicit save. cancel discards a draft, remove deletes a saved portal.
• list shows saved portals and, separately, the player's open drafts. show draws the outlines as particles, only for the executing player.
• Box from two corners (pos1/pos2, block-inclusive). Ring from eye position and look direction (centre rounded to 0.5, normal snapped to an axis within 5 degrees) plus a radius. Every portal has a task and an optional permission.
• Guided flow /setup portal create <id> with clickable buttons. Each button runs an existing sub-command, so the flow is a thin layer over the commands and not a second code path. Buttons are built with the Adventure API, never with MiniMessage click tags around player text.
• Live particle preview while a draft is open (max 256 points, per player, cleaned up on save, cancel and quit).
• Tab completion: ids, tasks taken from saved portals, radii, none.
• Validation reuses core PortalValidator.problems(...), the same rules that abort the lobby's startup, so an invalid portal is never written. Saving keeps spawn, name, authors and the other portals.

Notes

• Messages are English in the MapCommand style (the repository has no i18n infrastructure).
• /setup has no permission check yet (follow-up).
• The lobby reads portals only at startup, so it needs a restart after edits.
• A wand item is a possible follow-up.
• README: new "Portals" subsection under the setup server docs.

Tests

New test classes under setup/src/test: DiscPlacementTest, PortalEditorTest, PortalEditorValidatorParityTest, PortalMessagesTest, PortalEditorLoggingTest, PortalOutlineTest, DraftOutlineTest, MapProviderPortalStoreTest, DraftPointsTest, PortalShowTest, DraftPreviewTest, PortalCommandTest, PortalFlowTest, PortalCompletionsTest.

./gradlew build is green. The manual in-game check (clickable buttons, tab completion in the real client) is still pending and will be done before merge.

OpenSpec

openspec/changes/setup-portal-command

https://claude.ai/code/session_01A7aAe2E6wAEbi6jjnyPTWH

[github-actions]

Test results

  345 files    345 suites   21m 10s ⏱️
  729 tests   728 ✅ 1 💤 0 ❌
2 187 runs  2 184 ✅ 3 💤 0 ❌

Results for commit 19f7bb9.

♻️ This comment has been updated with latest results.

[TheMeinerLP]

Manual in-game test passed (local setup server + local lobby, offline mode):

• Guided flow /setup portal create: all buttons (shape, set corner/centre, radius, task, permission, save) worked in the real client; tab completion worked.
• Saved a ring (disc, radius 9, normal snapped to -x) and a box portal; map.json kept spawn/name/builders.
• Lobby (feat(portal): switch servers by walking or flying through portals #326) delivered once per pass through both portals (DebugDeliver), in world and — with the portals copied by hand — in the halloween season world.

https://claude.ai/code/session_01A7aAe2E6wAEbi6jjnyPTWH