feat(codebuddy-cn): replace deepseek-v4-flash with deepseek-v4.1-flash

The server's product-config payload (which the IDE plugin fetches from
copilot.tencent.com) publishes deepseek-v4.1-flash and no longer lists
deepseek-v4-flash, so the old id is dropped — same pattern as the previous
catalog refreshes (#3648, #3802). The v4-flash endpoint still answers 200,
but the published list is the contract.

Per the server table, maxOutput rises 50000 -> 128000 while contextWindow
stays 1000000.

- registry/codebuddy-cn.js: models[] entry swapped to the new id
- capabilities.js: per-model entry swapped, maxOutput -> 128000

No changes needed in thinkingLevels.js (the deepseek-v4* pattern already
matches the new id and publishes low/high/xhigh, matching the server's
supportedEfforts or pricing.js (the deepseek-v* glob yields the same rates).
EOF
)

open-sse/providers/capabilities.js

@@ -209,7 +209,10 @@ export const PROVIDER_CAPABILITIES = {
     "glm-5.3-flash":      { vision: true, reasoning: true, thinkingFormat: "openai", thinkingCanDisable: true, contextWindow: 1000000, maxOutput: 32000 },
     "kimi-k3-1":          { vision: true, reasoning: true, thinkingFormat: "openai", thinkingCanDisable: false, contextWindow: 1000000, maxOutput: 32000 },
     "deepseek-v4-pro":    { vision: true, reasoning: true, thinkingFormat: "openai", thinkingCanDisable: true, contextWindow: 1000000, maxOutput: 50000 },
-    "deepseek-v4-flash":  { vision: true, reasoning: true, thinkingFormat: "openai", thinkingCanDisable: true, contextWindow: 1000000, maxOutput: 50000 },
+    // deepseek-v4.1-flash replaces v4-flash (dropped from the server list;
+    // the old endpoint still answers 200 but the published list is the
+    // contract). maxOutput 128000 per the server's product-config payload.
+    "deepseek-v4.1-flash": { vision: true, reasoning: true, thinkingFormat: "openai", thinkingCanDisable: true, contextWindow: 1000000, maxOutput: 128000 },
   },
   // Qoder — upstream exposes opaque internal ids (dfmodel, kmodel, …); the
   // registry `name` is display-only and capability lookup matches on the raw