feat(i18n): add fr_CA translation and apply string context rule #minor

[Revenantal]

Context

Wicket: none
Related PRs: industrialdev/wicket-wp-base-plugin#63, industrialdev/wicket-wp-theme#19, industrialdev/wicket-wp-financial-fields#10

What

• Adds a Canadian French (fr_CA) translation (.po, .mo, .l10n.php) for all 1,040 strings in wicket-acc.pot, including plurals.
• Applies the short-string context rule across the plugin and its ACF field strings.
• Scopes ACF translation to the Account Centre's own fields and makes ACF strings extractable.
• Fixes the Account Center label for sites set to account-center.

Why

Many Account Centre strings were missing context, were split into fragments, or were translated through a site-wide ACF filter that affected other plugins. Wicket now ships fr_CA, following the Atlas translations convention (conv.stack.translations).

How

Contexts and strings

• Every 1 to 3 word string gets a gettext context that names its kind (label, button label, status, message, and so on). Full sentences drop their contexts. Specific contexts stay only where the same text has a different meaning (role name, relationship type).
• Ambiguous strings and abbreviations get translator comments. Inline translator comments move onto their own lines so make-pot attaches them to the right string.
• "the contact" / "the member" fragments become full sentences. The cascade seat-limit error is now wrapped in __().

ACF

• An acf/prepare_field filter replaces the site-wide acf/settings/l10n_textdomain filter. It translates only fields from includes/acf-json.
• composer i18n:acf (.ci/acf-i18n-strings.php) generates languages/acf-strings.php, so make-pot extracts ACF strings with a context.

Fixes

• getAccName() now returns "Account Center" when the site uses the center setting.
• The VitalSource action label now reads "eBook Fulfilment". The stored value is unchanged, so MDP matching still works.
• The .pot hook runs faster and supports package excludes.

Impact on existing translations

Re-contexted strings no longer match existing site translations. We accepted this because client translation coverage is under 1% and fr_CA now ships with the plugin. Site-level translations (Loco, wp-content/languages) still take precedence.

[EstebanForge]

Approved. Same shape as the base plugin PR and it holds up. What I verified:

• msgfmt --check passes on the fr_CA catalog (1041 messages), the shipped .mo matches, and the .l10n.php is valid with matching plural rules. CI pot check is green, so the pot is in sync with source.
• The domain-load fix is real: the old dirname(plugin_basename(__FILE__)) . '/languages/' pointed at src/languages/, which never existed, so bundled translations never loaded. The new root-relative load on init priority 1, admin included, fixes it.
• The ACF pipeline is guarded: translate_acf_field() only touches field keys collected from includes/acf-json, and .ci/acf-i18n-strings.php mirrors the runtime context map and the 1-to-3-word rule exactly.
• WP_Error codes are unchanged across services, the touchpoint display_type branches only exist in blocks whose signature has the parameter, and the added escaping (wp_die, email bodies, template-not-found) is a real hardening. Good riddance to the hardcoded njbia.org in the welcome email, now the site's own host.

Two nits, fine to fix later:

1. Same slug, two source strings: getAccPageTitles() uses "Bulk Upload Members" while RequiredPagesNotice::pageTitles() uses "Organization Members Bulk Upload". Different admin screens can show different titles for the same page. Please pick one.
2. The 1-to-3-word rule and the setting-to-context map now live in two places (Blocks.php runtime, .ci/acf-i18n-strings.php generator). A future drift makes ACF strings silently untranslatable. Please consider generating the map from one source, or a test that diffs the two.

Two behavior notes so nobody is surprised: handleWooCommerceMyAccountPage() now uses the translated title, so on a French site the safeguard pass renames the actual WooCommerce My Account page to French (slug stays my-account, URLs are safe). And the ui:i1e8n to ui:i18n fix in Schema means enumNames localization now actually applies where it silently never did.

Thanks Adrian, solid work across 171 files.