Document gemini-2.5-flash as withdrawn rather than superseded (#367)

Gemini availability is scoped to the calling project. This model still answers
for some long-lived keys while returning "no longer available to new users" for
others, so it was described as superseded-but-working on the strength of a key
that could still reach it — which says nothing about anyone else's project.

Aligns its deprecation note with the rest of the 2.x members. Behaviour is
unchanged: a hint naming it already resolves to a current model.


Claude-Session: https://claude.ai/code/session_01Y9GNwKEBkEAoLYzkTngfGk

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: KrisBraun

.changeset/gemini-25-flash-withdrawn.md

@@ -0,0 +1,11 @@
+---
+"@plotday/twister": patch
+---
+
+Changed: `AIModel.GEMINI_25_FLASH` is documented as withdrawn rather than
+merely superseded, matching the other 2.x members.
+
+Gemini availability is scoped to the calling project: this model still answers
+for some long-lived keys while returning "no longer available to new users" for
+others, so a model resolving for you is not evidence that it resolves for
+everyone. It is remapped to a current model like the rest of the generation.

twister/src/tools/ai.ts

@@ -269,7 +269,7 @@ export enum AIModel {
   // rather than failing — but new code should name a 3.x member directly.
   /** @deprecated Withdrawn by Google. Use {@link AIModel.GEMINI_31_PRO}. */
   GEMINI_25_PRO = "google/gemini-2.5-pro",
-  /** @deprecated Superseded. Use {@link AIModel.GEMINI_35_FLASH}. */
+  /** @deprecated Withdrawn by Google. Use {@link AIModel.GEMINI_35_FLASH}. */
   GEMINI_25_FLASH = "google/gemini-2.5-flash",
   /** @deprecated Withdrawn by Google. Use {@link AIModel.GEMINI_35_FLASH_LITE}. */
   GEMINI_25_FLASH_LITE = "google/gemini-2.5-flash-lite",