Upgrade default Claude Opus model to 4.8

Bump the default Opus route/model from claude-opus-4-7 to claude-opus-4-8
across provider presets (claude, claudeDesktop, hermes, openclaw, opencode,
universal), i18n locales (zh/en/ja/zh-TW), pricing seed data, and the
user-manual docs.

- Add claude-opus-4-8 pricing row ($5/$25/$0.50/$6.25); keep the 4-7 row
  for historical usage stats (seeded via INSERT OR IGNORE).
- Claude Desktop proxy: accept bidirectional opus 4-7 <-> 4-8 route alias
  during rollout so previously saved routes keep resolving.
- thinking_optimizer: route opus-4-8 through adaptive thinking and normalize
  dotted model ids (also fixes dotted 4-6/4-7 falling back to legacy).
- usage_stats: normalize Bedrock/Vertex/aggregator opus-4-8 ids to base
  pricing.

Also merge role:"system" messages into the Gemini systemInstruction in the
Anthropic->Gemini transform.

src/components/providers/forms/HermesFormFields.tsx

@@ -415,7 +415,7 @@ export function HermesFormFields({
                           handleModelChange(index, "id", e.target.value)
                         }
                         placeholder={t("hermes.form.modelIdPlaceholder", {
-                          defaultValue: "anthropic/claude-opus-4-7",
+                          defaultValue: "anthropic/claude-opus-4-8",
                         })}
                         className="flex-1"
                       />
@@ -471,7 +471,7 @@ export function HermesFormFields({
                         handleModelChange(index, "name", e.target.value)
                       }
                       placeholder={t("hermes.form.modelNamePlaceholder", {
-                        defaultValue: "Claude Opus 4.7",
+                        defaultValue: "Claude Opus 4.8",
                       })}
                     />
                   </div>