fix(cjk): hide CJK textarea on welcome screen and fix vertical centering

- Guard `_updateCjkInputState()` with `activeSessionId` check so the
  `position: fixed` CJK textarea doesn't float over the welcome overlay
- Call `_updateCjkInputState()` in `showWelcome()`/`hideWelcome()` to
  sync CJK visibility on session enter/leave
- Add `padding: 12px 10px` to `.cjk-input-visible textarea` for proper
  vertical centering of input text

src/web/public/app.js

@@ -2103,7 +2103,13 @@ class CodemanApp {
     // Mobile defaults ship cjkInputEnabled: false (native terminal input by
     // default on touch), but an explicit user enable is honored everywhere —
     // the App Settings toggle must not be a silent no-op on phones.
-    const showCjk = this._serverCjkOverride || (settings.cjkInputEnabled ?? defaults.cjkInputEnabled ?? false);
+    // The welcome/home screen (no active session) has nothing to type into.
+    // Force-hide the CJK textarea there — otherwise the `position: fixed`
+    // `.cjk-input-visible` rule floats it over the welcome overlay and blocks
+    // content. Re-synced on session enter/leave via hideWelcome()/showWelcome().
+    const cjkUserEnabled =
+      this._serverCjkOverride || (settings.cjkInputEnabled ?? defaults.cjkInputEnabled ?? false);
+    const showCjk = cjkUserEnabled && !!this.activeSessionId;
     cjkEl.classList.toggle('cjk-input-visible', !!showCjk);
     document.body.classList.toggle('cjk-input-visible', !!showCjk);
     cjkEl.style.display = showCjk ? 'block' : 'none';

src/web/public/styles.css

@@ -8778,6 +8778,7 @@ kbd {
   display: block;
   min-height: 44px;
   max-height: 96px;
+  padding: 12px 10px;
   border: 1px solid rgba(80, 120, 190, 0.55);
   border-left: none;
   border-right: none;

src/web/public/terminal-ui.js

@@ -943,6 +943,9 @@ Object.assign(CodemanApp.prototype, {
       this.loadTunnelStatus();
       this.loadHistorySessions();
     }
+    // Home screen has no input target — hide the CJK textarea (activeSessionId
+    // is null by the time we get here). Guarded: defined on the app object.
+    this._updateCjkInputState?.();
   },
 
   hideWelcome() {
@@ -956,6 +959,9 @@ Object.assign(CodemanApp.prototype, {
       clearTimeout(this._welcomeQrShrinkTimer);
       qrWrap.classList.remove('expanded');
     }
+    // Entering a session — restore CJK textarea if the user has it enabled
+    // (activeSessionId is already set by selectSession before this call).
+    this._updateCjkInputState?.();
   },
 
   /**