docs: changelog entries for xAI Grok OAuth, image-gen xai branch, and tts tool

Notes the new xAI Grok OAuth provider in /login, the XAI_OAUTH_TOKEN
env-var fallback, the four new optional fields on OpenAIResponsesOptions,
the generate_image xai branch, and the new tts tool.

Op: extend

packages/ai/CHANGELOG.md

@@ -1,6 +1,15 @@
 # Changelog
 
 ## [Unreleased]
+### Added
+
+- xAI Grok OAuth (SuperGrok Subscription) provider in `/login`. Loopback PKCE flow on `127.0.0.1:56121`; the token unlocks Grok-4.x chat. Ported from NousResearch/hermes-agent (MIT).
+- `XAI_OAUTH_TOKEN` environment variable accepted as a headless fallback for the xAI Grok OAuth provider.
+
+### Changed
+
+- `OpenAIResponsesOptions` gains four optional, provider-agnostic fields that adapter wrappers can use to compose provider-specific behavior on top of the generic transport: `includeEncryptedReasoning` (gates `include: ["reasoning.encrypted_content"]`; default `true`, preserves current behavior), `filterReasoningHistory` (strips replayed `type: "reasoning"` items from conversation history; default `false`), `headers` (merged onto the client's default headers), and `extraBody` (merged into the request payload).
+- The existing `XAI_API_KEY` path is unchanged — it continues to use the OpenAI-completions transport.
 
 ## [15.5.6] - 2026-05-27
 ### Added

packages/coding-agent/CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 
 ## [Unreleased]
+### Added
+
+- `generate_image` accepts `provider=xai` (Grok Imagine). Supports `grok-imagine-image` (default) and `grok-imagine-image-quality` at aspect ratios `1:1`, `16:9`, `9:16`, `4:3`, `3:4`, `3:2`, `2:3`. Uses the xAI Grok OAuth credential when available, otherwise `XAI_API_KEY`.
+- New `tts` tool synthesises speech via xAI Grok Voice. Built-in voices `ara`, `eve` (default), `leo`, `rex`, `sal`; custom voice IDs also accepted. Output codec inferred from the `output_path` suffix (`.wav` → `wav`, else `mp3`). Up to 15,000 characters per request.
 
 ## [15.5.6] - 2026-05-27
 ### Added