PT-4578: Zoom in / out / reset in the tab menu, Power and Simple

[rolfheij-sil]

Stacked on #2803 (pt-4576-content-zoom-platform-core). Review only the commits above that branch. Stacked PRs get no automatic CI here; the full local battery (typecheck, lint, format:check, vitest run src: 264 files / 3838 tests; platform-bible-utils 611 tests) is green. After #2803 squash-merges this branch is rebased with git rebase --onto main <old parent tip>.

Summary

Work item 3 of the per-pane content-zoom epic (PT-4575): Zoom in / Zoom out / Reset zoom to default in the web-view tab's right-click menu, in Power mode and in Simple mode.

• Power mode, data only. A new platform.tabZoom group (order 50, not extensible, isExperimental) with three items bound to the owner-routed commands from PT-4576: Platform core for per-pane content zoom #2803, ahead of the existing window group. The tab-menu handler already passes the tab id, which is the web-view id, so each item acts on exactly that tab. en/es strings added.
• Simple mode gets a tab menu for the first time, holding only the zoom group. The tab title component now reads the contributed menu in both modes and narrows it to platform.tabZoom in Simple mode before conversion (the converter flattens groups, so the filter has to happen on the raw contributed menu). It renders nothing until the interface mode is known, so a Power user is never shown the Simple menu during startup. The drag-ignore marker is passed onto the menu trigger so Simple mode's fixed layout stays fixed; the keyboard path (Shift+F10 / Menu key) now works wherever a menu exists.
• A tab hosting no web view (a dialog or error tab) gets no zoom items, following the existing rule for the move items. On a web view that marks no zoom area the items stay and are inert: the service already treats such a request as a silent no-op, and the only "has areas" signal is filled asynchronously as the pane bootstraps, so disabling on it would show disabled items that in fact work.

PT-3171 (View menu on tabs) is fulfilled by this item; the closure note belongs with PT-4585.

Why review this

Part of the current epic (PT-4575). It is the discoverable entry point for content zoom (NN-7) and the first UI Simple mode offers on a tab (NN-9).

Decisions worth a look

• Simple mode reaches the tab menu only on Column 3. Simple mode's Home and Scripture Editor columns use a headless tab bar (dock-layout-wrapper.simple-mode.scss: pointer events off, opacity 0), so there is no editor tab to right-click. Decision (Epic Lead via Rolf, 2026-09-15): Simple mode needs editor zoom too, and the entry point is the Scripture editor's own hamburger menu (Options column), visible in both modes; that lands with PT-4581 alongside the editor's zoom areas. Recorded in the new ADR adr-simple-mode-tab-menu-offers-zoom-only. The Home column (model text) has no menu of any kind and keeps only the chords; a separate UX question.
• isExperimental on the group only. The menu-item schema has no such property and rejects unknown ones (unevaluatedProperties: false), so an item-level marker would fail startup validation; the existing platform.tabWindow group carries it the same way.
• Order 50 is now reserved. WebViewMenu.tabMenu's TSDoc told extensions the platform occupies order 100; it now says 50 and 100, in the source and in the regenerated platform-bible-utils/dist (that rebuild also carries a formatting-only rewrap of one unrelated TSDoc paragraph).
• Simple mode now pays one getWebViewMenu read per tab at mount (six tabs in the fixed layout), where it paid none; a single read per tab, not a subscription.
• Spanish follows the ticket ("Acercar" / "Alejar" / "Restablecer zoom al valor predeterminado"); a reviewer may prefer "Restablecer el zoom …" to match the neighbouring strings' articles.
• One pre-existing test updated: menu-data.service-host.test.tsx hard-coded the full list of shipped tab-menu commands and now expects the three zoom commands ahead of the window ones.

Testing

• New menu.data.test.ts (group shape and order, item commands and orders pinned to CONTENT_ZOOM_COMMANDS, labels, no item-level isExperimental, shipped document still validates).
• tab-menu.util.test.ts: filterTabMenuToGroup (happy path, absent group, cross-group items dropped, input not mutated, cross-check against the shipped JSON) and the no-web-view availability rule.
• New platform-tab-title.zoom-menu.test.tsx (11 cases: Power-mode order, Simple-mode contents, dispatch with the tab id in both modes, mode-not-known gate, Simple mode reads the menu once and never reads the window list, no-web-view tab in both modes, drag-ignore on title and trigger, nothing before the read lands, keyboard forwarding in Simple mode). Two existing tab-title test files gained the interface-mode mock and one rewritten expectation.
• Root and platform-bible-utils batteries green (see the stacked note); roborev per-commit reviews triaged on every commit (one fixed: a type-assertion suppression replaced by a ReferencedItem parameter type).
• Self-review: /review-paratext (four analyzer passes) and an OpenCodeReview delegate pass ran on the branch. No Critical. Fixed here: one interface-mode subscription per tab title instead of two; the keyboard-shortcuts catalog entry for the tab menu now covers both modes; translator notes say the items act on the pane last used in the tab, not the whole tab; backward-facing comments reworded; CONTENT_ZOOM_TAB_MENU_GROUP moved to the shared content-zoom model with the JSON pin test next to the menu data; an act() warning and a redundant test removed; Spanish reset label takes the article. Items stay inert on a view with no zoom area (the "has areas" signal is asynchronous, so disabling would show disabled items that work); the three tab-title test files still each carry their own mock harness.
• No e2e added: PT-4585 runs the Simple/Power matrix. Manual check in the running app pending (Power editor tab, dialog tab, Simple Column-3 tab, keyboard).

Risk Level

Medium. Changes the tab title component every tab renders, in both modes; the Simple-mode behaviour is new.

AI-assisted — Claude Code (Fable 5.1 coordinating; Opus design pass; per-task Sonnet agents under TDD; Sonnet verification pass).

🤖 Generated with Claude Code

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This change is 

[rolfheij-sil]

🤖 Claude: Superseded by #2821, which combines this PR with the other content-zoom work items into one PR stacked on #2803. All commits are preserved there unchanged.