Add Opus 4.8 model

New Anthropic flagship released 30 May 2026. Adds the dropdown entry as
the new default for fresh agents, maps "opus-4-8" -> "claude-opus-4-8" in
ResolveModelId, and bumps the "opus" alias from 4.7 to 4.8 so the family
shortcut tracks the latest release.

ARCHITECTURE.md updated to list opus-4-8 in both the field reference and the
model-resolution block.

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

ARCHITECTURE.md

@@ -844,7 +844,7 @@ Ein **Agent** definiert die Persönlichkeit und Fähigkeiten der AI:
 |-------------------|------------------------------------------------------------------|
 | `Name`            | Anzeigename                                                     |
 | `Avatar`          | Base64 Data-URL (WebP, 512px) + `AvatarSmall` (WebP, 256px Thumbnail) |
-| `Model`           | `sonnet`, `sonnet-4-5`, `sonnet-4-6`, `opus`, `opus-4-5`, `opus-4-6`, `opus-4-7`, `haiku`, `haiku-4-5` (Default für `opus` ist `claude-opus-4-7`) |
+| `Model`           | `sonnet`, `sonnet-4-5`, `sonnet-4-6`, `opus`, `opus-4-5`, `opus-4-6`, `opus-4-7`, `opus-4-8`, `haiku`, `haiku-4-5` (Default für `opus` ist `claude-opus-4-8`) |
 | `CustomCommands`  | JSON-Array mit Slash-Commands (Label + Prompt)                   |
 | `AutoCommit`      | `""` (nichts), `"mention"` (anmerken – nur auf User-Request), `"enforce"` (erzwingen – nach jeder Änderung), `"forbid"` (strikt verboten) |
 | `UseSoul`         | SOUL.md in System-Prompt einbinden                               |
@@ -862,10 +862,11 @@ Ein **Agent** definiert die Persönlichkeit und Fähigkeiten der AI:
 "sonnet"          → claude-sonnet-4-6
 "sonnet-4-5"      → claude-sonnet-4-5
 "sonnet-4-6"      → claude-sonnet-4-6
-"opus"            → claude-opus-4-7
+"opus"            → claude-opus-4-8
 "opus-4-5"        → claude-opus-4-5
 "opus-4-6"        → claude-opus-4-6
 "opus-4-7"        → claude-opus-4-7
+"opus-4-8"        → claude-opus-4-8
 "haiku"           → claude-haiku-4-5
 "haiku-4-5"       → claude-haiku-4-5
 (default)         → claude-sonnet-4-6

Services/ChatService.cs

@@ -44,10 +44,11 @@ public class ChatService
             "sonnet" => "claude-sonnet-4-6",
             "sonnet-4-5" => "claude-sonnet-4-5",
             "sonnet-4-6" => "claude-sonnet-4-6",
-            "opus" => "claude-opus-4-7",
+            "opus" => "claude-opus-4-8",
             "opus-4-5" => "claude-opus-4-5",
             "opus-4-6" => "claude-opus-4-6",
             "opus-4-7" => "claude-opus-4-7",
+            "opus-4-8" => "claude-opus-4-8",
             "haiku" => "claude-haiku-4-5",
             "haiku-4-5" => "claude-haiku-4-5",
             _ => "claude-sonnet-4-6"

wwwroot/index.html

@@ -203,7 +203,8 @@
           <option value="sonnet-4-6">sonnet-4-6</option>
           <option value="opus-4-5">opus-4-5</option>
           <option value="opus-4-6">opus-4-6</option>
-          <option value="opus-4-7" selected>opus-4-7</option>
+          <option value="opus-4-7">opus-4-7</option>
+          <option value="opus-4-8" selected>opus-4-8</option>
           <option value="haiku-4-5">haiku-4-5</option>
           <optgroup label="OpenAI" id="openaiOptgroup">
             <option value="" disabled>Wird geladen...</option>