✨ feat: editor-defined OG image and description

[jbourdin]

Summary

Editor-defined Open Graph image and description controls across decks, archetypes, archetype variants, and the Banned/Staple Cards listing pages — bundling F18.30 and F18.31 because they share an OgMetaResolver service and a single PR is browser-validatable end-to-end.

• Data model. Three new column pairs (all nullable): deck.og_image/og_description (non-translatable); archetype_translation.og_image/og_description (per-locale, kept independent from meta_description so length is tunable for social cards); page_translation.og_image/og_description (per-locale override on top of the existing parent-level Page.ogImage). Migration is hand-pruned to only these six ADD COLUMNs — the auto-generated diff carried 30+ unrelated drift lines that have been stripped.
• Resolver. New App\Service\Seo\OgMetaResolver (stateless, no injected deps) centralises the fallback chain. For decks: own values → (if isArchetypeVariant()) archetype translation → currentVersion.mosaicImageUrl. For archetypes: translation OG → graceful fallback to localizedMetaDescription. For pages: translation override → parent Page.ogImage → none.
• Controllers. DeckShowController, ArchetypeDetailController, BannedCardController, StapleCardController inject the resolver and pass the resolved ogImage/ogDescription into their templates. AdminPageController::duplicate() also copies the new per-locale fields when cloning a page.
• Templates. Existing _partials/opengraph.html.twig already null-guards both fields, so no partial change. staple_card/list.html.twig gains a full {% block opengraph %} block (it had none). The other three templates feed the new vars through their existing block.
• Admin UX. New ogImage inputs render with the existing ImageUrlField Mantine drag-and-drop component via the admin/_image_url_field.html.twig macro — the same UX as the homepage editor and the parent-level Page.ogImage. The React mount loop is extracted to assets/shared/mount-image-url-field.tsx and reused from page-form, deck-form, and archetype-form Webpack entries (page-form's previously-inline copy was replaced by the same call).
• Translations. 14 new keys across messages.{en,fr}.xlf (app.form.label.og_*, app.archetype.og_*_label/help, app.cms.form.og_*_localized*). Per-locale og_image_localized is kept distinct from the parent-level app.cms.form.og_image so editors don't see the same label twice on the same admin page.
• Tests. 13 new unit tests in OgMetaResolverTest cover variant fallback, meta-description graceful fallback, page translation/parent precedence, and missing-translation paths. 2 new functional tests on BannedCardController assert that og:image/og:description render from editor input and degrade gracefully when blank.
• Docs. docs/features.md (new F18.30 and F18.31 rows), docs/models/deck.md, docs/models/cms.md.

One design call worth flagging

og_title for Banned/Staple keeps the existing 'app.banned_card.public.title'|trans style rather than reusing PageTranslation.title, because PageTranslationFormType hides the title field when is_listing_intro is true (lines 35-39) — so title for listing intros isn't editor-controlled. If editors want a separate social-share title later, the upgrade is PageTranslation.ogTitle.

Test plan

• Admin: edit a deck → set OG image (drag-and-drop) and OG description → save → view the public deck page source and confirm og:image + og:description reflect the editor values.
• Admin: edit an archetype's EN translation, set OG fields, save; do the same for FR. Confirm /en/archetypes/<slug> and /fr/archetypes/<slug> each render their locale-specific OG values.
• Variant fallback: clear a variant deck's own OG fields and confirm the page falls back to the parent archetype's locale-scoped values; set the variant's own values and confirm they win.
• Listing pages: edit the banned-cards intro Page → set per-locale OG values → confirm /en/banned-cards and /fr/banned-cards emit correct meta. Repeat for staple cards (/en/staple-cards, /fr/staple-cards).
• Empty-state safety: with all new fields blank, none of the five pages regresses — the deck page still emits the mosaic as og:image, the archetype page still emits localizedMetaDescription as og:description, and the banned/staple pages continue to emit og:title + og:url as before.
• Drop a JPG, PNG, GIF, and WebP into the drag-and-drop zone on each form and confirm upload → preview → URL persisted.
• Paste a malformed URL (e.g. not-a-url) into the OG image field and confirm the regex validation (#^(/|https?://)#) rejects on submit.
• Social validators: paste one URL from each surface into the Facebook Sharing Debugger and the Twitter Card Validator; confirm both EN and FR previews render the expected image + description.

Closes #580, closes #581.

[sentry]

Codecov Report

❌ Patch coverage is 93.85965% with 7 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/Controller/StapleCardController.php	0.00%	5 Missing ⚠️
src/Controller/AdminPageController.php	0.00%	2 Missing ⚠️

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