set-key takes the ref it was given, and a key inline

`claude-mode set-key openrouter sk-or-...` did the wrong thing on the
POSIX port: the dispatcher loop kept the *last* positional, so the key
became the ref name and the prompt asked for "the key for ref
'sk-or-...'". Storing to that ref succeeds, so nothing looks wrong until
the switch later reports no key for 'openrouter' - which is exactly what
happened on macOS.

Both ports now take `set-key [ref] [key]`: the first positional is the
ref unless it is key-shaped (sk-* or longer than a ref name would
plausibly be), in which case it is the key for the default ref, and a
second positional is always the key. An inline key warns that it is now
in the shell history, since the hidden prompt leaves no trace. Extra
arguments are refused instead of ignored. The Windows dispatch already
read the first positional correctly, so it only gains the inline form.

The shipped default preset moves to the models asked for: DeepSeek 4.1
Flash on opus, GLM Flash on sonnet. Existing installs keep their own
presets - the installer never overwrites one without --force - so an
upgrade needs `claude-mode preset set default opus ...` and the same for
sonnet, or a --force install.

Verified in the bash 3.2 container: ref+key stores under the ref, a bare
key stores under openrouter, an empty prompt aborts, a custom ref still
works, the stored value is byte-identical, and four positionals are
refused.

Co-Authored-By: Claude Code <noreply@anthropic.com>

presets/default.json

@@ -1,14 +1,14 @@
 {
   "provider": "openrouter",
-  "description": "Daily driver. Flash-class models on the hot tiers, GLM on fable.",
+  "description": "Daily driver. DeepSeek 4.1 Flash on opus, GLM Flash on sonnet, GLM on fable.",
   "baseUrl": "https://openrouter.ai/api",
   "auth": {
     "mode": "vault",
     "keyRef": "openrouter"
   },
   "models": {
-    "opus": "z-ai/glm-5.3-flash",
-    "sonnet": "deepseek/deepseek-v4-flash-0731",
+    "opus": "deepseek/deepseek-v4.1-flash",
+    "sonnet": "z-ai/glm-5.3-flash",
     "haiku": "openrouter/free",
     "fable": "z-ai/glm-5.3"
   },