Systems 7: every page reads through page and follows

[Pelotrio]

Seventh PR of docs/SYSTEMS.md, stacked on #117: every page reads through the one PageLoader way, page and follows, and the older modes and ShownUpdates go.

Finish line

Behavior	Test
The World tab names the world the game plays while its page is hidden, and the hidden page reads nothing for it	PageReadsTest.theWorldTabNamesTheWorldTheGamePlaysWhileItsPageIsHidden
When the game plays another world, followers of the world's owner find it read when told	WorldReadingTest.whenTheGamePlaysAnotherWorldItsFollowersFindItsNamePublished (fails without the change)
A redraw from memory waits while the page is hidden, runs once when shown, and not after the page closed	PageLoaderTest.anUpdateFromMemoryWaitsWhileThePageIsHiddenAndRunsOnceWhenShown
A tab's title is redrawn while its page is hidden	PageLoaderTest.aTitleIsRedrawnWhileThePageIsHidden
A page reading whenever shown waits while hidden; a part of a page reads when chosen	PageLoaderTest.aPageReadWheneverShownWaitsWhileHidden, aPartOfThePageReadsWhenItIsChosenAndChangesFollowWhileThePageIsShown
The Changes, configuration and pack configuration pages read once shown, as tabs show them	ChangesPanelTest, ConfigPanelTest, PackConfigurationPanelTest (their pages are shown now)
No page keeps an old mode	SystemsRulesTest; PageLoader runs its reads on the file workers, so its exception is gone

What changes

• PageLoader keeps one way: page, follows, hold/release, and readsWhenShown for the pages whose files others write and only they read. whenShown, waitsWhileHidden and follow(Function) go. It gains updates(signal, redraw) for redraws from memory, PageLoader.redraws(page) for a page with nothing to read, and retitles(signal, redraw) for what shows outside the page. Reads run on the file workers.
• ShownUpdates goes; its users (Logs, Content, Mod, World, definition details, subject pages) redraw through their loader.
• Pages: Changes, Logs, configuration, pack configuration, pack, resource packs, Mod, World and definition details use page and follows. None reads in its constructor, and navigation no longer refreshes the Changes and pack configuration pages. The Logs page reads again only when a navigation asks for a log it does not list yet, as a crash report written since.
• Log navigation clears an older pending selection when the requested file is already listed.
• ChangeLabels.follows() names the signals of values that change outside the record, instead of taking a listener.
• resourcesRead, what Mod pages and definitions follow for the game reading its resources again, is a Signal.
• The World tab follows connection changes as well as world changes, so disconnecting retitles a hidden server tab. It names the world from its owner's published value, redrawn when the owner or what the game plays changes, whether the page is shown or not. WorldReading tells its followers of another world once that world was read, and FileReading.published() gives the value read last without reading.
• docs/SYSTEMS.md describes the redraws, and moves the Project tree, the CompanionUi relays, ChangeRecord.observed and the Changes page's read whenever shown to PR 8, with the current project as state and the write queue they need.

Left as it is

• The Changes page reads whenever it is shown until the owners notice values put back outside Companion (PR 8).
• The configuration page reads again after its own save, through its writer; the configuration files have no owner that reads them.
• No test holds ExternalEdits' strand busy, so its take check is covered by review, not by a test.

Focused :companion:test checks pass locally. CI runs the full build for the updated head.

🤖 Generated with Claude Code

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-30T17:19:18.012661Z	d4e9891	New commits

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[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: d5e7629fe9

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[chatgpt-codex-connector]

Retitle the World tab when the connection ends

When a multiplayer connection drops without first receiving a Menu payload, GameLocation.disconnected() clears playing() but fires only connectionChanged(). This loader listens for title changes only on playingChanged() and world.changed(), and the latter need not fire when the previously published local world remains unchanged, so a hidden World tab can retain the disconnected server's address indefinitely. Retitle on connectionChanged() as well.

AGENTS.md reference: AGENTS.md:L19-L19

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[chatgpt-codex-connector]

Clear the older pending log selection

When a request for an unlisted crash report has set this.wanted and started a listing, a newer request for a file already present in this.files takes this branch but leaves the older wanted value intact. When the in-flight listing completes, showFiles() consumes that stale value and selects the older file again, so rapid navigation can make an older request override the newer one. Clear or replace the pending request before returning from this branch.

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