Chrome speaks the site's language: site.yaml lang + i18n table

The strings the portal itself says - Asked by, Also worth asking,
Sign in, the not-found page, defaults - translate via a small en/no
table selected by site.yaml's lang, which also sets the html lang
attribute. Content keeps speaking for itself; unknown languages fall
back to English per key.

Also: a scheme-gated markdown image now swallows its alt text instead
of leaking it as stray text - this is the fix for the test that has
been red since 0.3.19 (publish is tag-triggered and does not gate on
the test workflow; caught late).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y42TyF8Zu7NGRR2893vNcZ

src/i18n.rs

@@ -0,0 +1,97 @@
+//! Chrome-string translations, selected by `site.yaml`'s `lang`.
+//!
+//! Content carries its own language; this covers only the strings the
+//! portal itself speaks around it ("Asked by", the nav lead, the
+//! not-found page...). Unknown languages and unknown keys fall back
+//! to English, so a typo degrades to the default instead of a blank.
+
+/// Translate `key` for `lang`. `en` is the reference table; every
+/// other language falls through to it for keys it doesn't carry.
+pub fn t(lang: &str, key: &str) -> &'static str {
+    if let Some(s) = lookup(lang, key) {
+        return s;
+    }
+    lookup("en", key).unwrap_or(key_missing(key))
+}
+
+fn lookup(lang: &str, key: &str) -> Option<&'static str> {
+    Some(match (lang, key) {
+        ("en", "also_worth_asking") => "Also worth asking",
+        ("en", "asked_by") => "Asked by ",
+        ("en", "contact_them") => "contact them",
+        ("en", "if_stuck") => " if you get stuck.",
+        ("en", "send") => "Send",
+        ("en", "sign_in") => "Sign in",
+        ("en", "nothing_here_yet") => "Nothing here yet.",
+        ("en", "nothing_here") => "Nothing here",
+        ("en", "back_to_start") => "back to the start",
+        ("en", "done") => "Done.",
+        ("en", "follows_answer") => {
+            "This page follows from an answer you don't seem to carry yet."
+        }
+        ("en", "owners_only") => {
+            "This part of the site is for organizational owners — sign in with that account to take a look."
+        }
+        ("en", "announcements") => "Announcements",
+
+        ("no", "also_worth_asking") => "Også verdt å spørre",
+        ("no", "asked_by") => "Stilt av ",
+        ("no", "contact_them") => "ta kontakt",
+        ("no", "if_stuck") => " om du står fast.",
+        ("no", "send") => "Send",
+        ("no", "sign_in") => "Logg inn",
+        ("no", "nothing_here_yet") => "Ingenting her ennå.",
+        ("no", "nothing_here") => "Ingenting her",
+        ("no", "back_to_start") => "tilbake til start",
+        ("no", "done") => "Ferdig.",
+        ("no", "follows_answer") => {
+            "Denne siden følger av et svar du ikke ser ut til å bære ennå."
+        }
+        ("no", "owners_only") => {
+            "Denne delen av siden er for organisasjonens eiere — logg inn med den kontoen for å ta en titt."
+        }
+        ("no", "announcements") => "Kunngjøringer",
+
+        _ => return None,
+    })
+}
+
+/// A missing key is a programmer error; render the key itself so it
+/// is findable, never a panic in a view.
+fn key_missing(key: &str) -> &'static str {
+    // Leak is bounded: keys are a small fixed set of literals.
+    Box::leak(key.to_string().into_boxed_str())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn norwegian_covers_the_english_table() {
+        for key in [
+            "also_worth_asking",
+            "asked_by",
+            "contact_them",
+            "if_stuck",
+            "send",
+            "sign_in",
+            "nothing_here_yet",
+            "nothing_here",
+            "back_to_start",
+            "done",
+            "follows_answer",
+            "owners_only",
+            "announcements",
+        ] {
+            assert!(lookup("en", key).is_some(), "en missing {key}");
+            assert!(lookup("no", key).is_some(), "no missing {key}");
+        }
+    }
+
+    #[test]
+    fn unknown_language_falls_back_to_english() {
+        assert_eq!(t("de", "sign_in"), "Sign in");
+        assert_eq!(t("en", "sign_in"), "Sign in");
+    }
+}