feat(codex): /personality slash + in-session app-server params (#1265)

* feat(codex): support /personality via in-session override

Intercept /personality in the Codex slash layer, keep the value in CLI
memory only, and forward it on thread/turn start when set. Unset means
omit the field so Codex config/thread defaults apply—no Hub DB or web UI.

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(codex): refuse fake /personality clear (sticky thread setting)

turn/start.personality sticks for later turns; omitting the field does not
restore config.toml. Drop default|auto|clear success paths and require an
explicit friendly|pragmatic|none instead.

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: Cursor <cursoragent@cursor.com>

cli/src/codex/utils/appServerConfig.ts

@@ -212,6 +212,9 @@ export function buildThreadStartParams(args: {
     if (args.mode.model) {
         params.model = args.mode.model;
     }
+    if (args.mode.personality) {
+        params.personality = args.mode.personality;
+    }
 
     const threadServiceTier = toAppServerServiceTier(args.mode.serviceTier);
     if (threadServiceTier !== undefined) {
@@ -293,5 +296,9 @@ export function buildTurnStartParams(args: {
         params.serviceTier = turnServiceTier;
     }
 
+    if (args.mode?.personality) {
+        params.personality = args.mode.personality;
+    }
+
     return params;
 }