feat: derive AI model list from Raycast SDK enum

Generate MODEL_OPTIONS at runtime from AI.Model (dedupe by value, drop
@deprecated aliases), so the AI-view dropdowns show every model the
installed @raycast/api ships — no more hand-maintained six-entry list.

Switch the summaryModel preference from a static dropdown to a textfield
holding a model ID. The discoverable picker lives in the AI views (now
fully dynamic), and the preference just stores the chosen default.

Drop duplicate MODEL_OPTIONS / CREATIVITY_OPTIONS constants from
summarize-email.tsx and reply-email.tsx; both pull from ./ai now like
the briefing and extract views already do.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -180,37 +180,12 @@
     },
     {
       "name": "summaryModel",
-      "title": "Standard-Modell für Zusammenfassungen",
-      "description": "Raycast-KI-Modell für „Email-Konversation zusammenfassen“. Benötigt Raycast Pro.",
-      "type": "dropdown",
+      "title": "Standard-Modell für AI-Befehle",
+      "description": "Raycast-KI-Modell-ID, vorausgewählt in den AI-Views. Die volle Modellliste ist dort als Dropdown verfügbar. Benötigt Raycast Pro.",
+      "type": "textfield",
       "required": true,
       "default": "anthropic-claude-sonnet-4-6",
-      "data": [
-        {
-          "title": "Claude 4.6 Sonnet",
-          "value": "anthropic-claude-sonnet-4-6"
-        },
-        {
-          "title": "Claude 4.7 Opus",
-          "value": "anthropic-claude-opus-4-7"
-        },
-        {
-          "title": "Claude 4.5 Haiku",
-          "value": "anthropic-claude-4-5-haiku"
-        },
-        {
-          "title": "OpenAI GPT-5.3 Instant",
-          "value": "openai-gpt-5.3-instant"
-        },
-        {
-          "title": "OpenAI GPT-4.1",
-          "value": "openai-gpt-4.1"
-        },
-        {
-          "title": "OpenAI GPT-4o mini",
-          "value": "openai-gpt-4o-mini"
-        }
-      ]
+      "placeholder": "anthropic-claude-sonnet-4-6"
     },
     {
       "name": "maxSessions",