feedback5: merge W5I — real i18n phase 1: shared/i18n.js (Chinese msgids, params, data names), English game texts from the official EN client data (data/i18n/en.json), the 中文 / English switch on the title screen and in 设置, title / lobby / room / settings converted, server toasts and ticker lines with msgid + params, tools/i18n.mjs, docs/I18N.md (PR #70's translations by @YuriRestia reused, credited)

Conflict: server/match/player/basics.js imports (W5G's checkNotOwned + W5I's msg / dn). data/i18n/en.json rebuilt on the merged data (tools/build-i18n.mjs --offline): the 自选 data adds texts of CN-only operators and modules the EN client lacks, so coverage is 97.6 % (skills 95.9, talents 95.1); the coverage floors in test/i18n-data.test.js and docs/I18N.md say so. Golden unchanged; i18n / lobby / match / ui suites 1144/1144 after the rebuild, i18n e2e 1/1.

public/css/screens/title.css

@@ -192,6 +192,8 @@
   animation: rise-in 600ms 140ms var(--ease-out) backwards;
 }
 .title-cn__colon { color: #f4f6f5; }
+/* English title (ui/lang.js): the display face, smaller so "Stronghold Protocol: Alliance" fits one line */
+.title-cn--latin { font-family: var(--font-display); font-size: .6rem; font-weight: 700; letter-spacing: .04em; text-transform: uppercase; white-space: nowrap; }
 .title-cn em { font-style: normal; color: var(--mint-500); text-shadow: 0 0 .26rem rgba(23, 249, 183, .45); }
 .title-tag {
   margin-top: .12rem;
@@ -241,6 +243,10 @@
 .title-invite .icon { width: .2rem; height: .2rem; }
 .title-invite b { font-size: .2rem; letter-spacing: .2em; color: #ffd08a; }
 .title-conn { display: flex; align-items: center; justify-content: center; gap: .1rem; min-height: .32rem; font-size: .14rem; color: var(--text-lo); }
+/* language switch (中文 | English) in the top-right corner */
+.title-lang { display: inline-flex; margin-bottom: .1rem; }
+.title-lang button { min-width: .74rem; height: .3rem; font-size: .14rem; cursor: pointer; }
+html[data-lang="en"] .title-login .btn--xl { letter-spacing: .3em; }
 .title-conn .ping { height: .26rem; font-size: .15rem; }
 
 .title-foot {