Revise changelog entries for service settings refactor

Split the single "changed" entry into separate "added", "changed", and "deprecated" entries for clarity. Add a note about the subtle behavior change in the deprecated set_model/set_voice/set_language methods.

changelog/3714.added.md

@@ -0,0 +1,19 @@
+- Added support for using strongly-typed objects instead of dicts for updating service settings at runtime.
+
+  Instead of, say:
+
+  ```python
+  await task.queue_frame(
+      STTUpdateSettingsFrame(settings={"language": Language.ES})
+  )
+  ```
+
+  you'd do:
+
+  ```python
+  await task.queue_frame(
+      STTUpdateSettingsFrame(update=DeepgramSTTSettings(language=Language.ES))
+  )
+  ```
+
+  Each service now vends strongly-typed classes like `DeepgramSTTSettings` representing the service's runtime-updatable settings.

changelog/3714.changed.md

@@ -1 +1 @@
-- ⚠️ Refactored service settings to use strongly-typed dataclasses (`TTSSettings`, `STTSettings`, `LLMSettings`, and service-specific subclasses) instead of plain dicts. Each service now exposes a `_settings` attribute with discoverable, typed fields. Dict-based `*UpdateSettingsFrame(settings={...})` is deprecated in favor of passing typed settings delta objects. For service maintainers, see changes in COMMUNITY_INTEGRATIONS.md.
+- ⚠️ Refactored runtime-updatable service settings to use strongly-typed classes (`TTSSettings`, `STTSettings`, `LLMSettings`, and service-specific subclasses) instead of plain dicts. Each service's `_settings` now holds these strongly-typed objects. For service maintainers, see changes in COMMUNITY_INTEGRATIONS.md.

changelog/3714.deprecated.2.md

@@ -0,0 +1 @@
+- Dict-based `*UpdateSettingsFrame(settings={...})` is deprecated in favor of passing typed settings delta objects with `*UpdateSettingsFrame(update={...})`.

changelog/3714.deprecated.md

@@ -1 +1,3 @@
 - Deprecated `set_model()`, `set_voice()`, and `set_language()` on AI services in favor of runtime updates via `TTSUpdateSettingsFrame`, `STTUpdateSettingsFrame`, and `LLMUpdateSettingsFrame`.
+
+  ⚠️ Note, too, a subtle behavior change in these deprecated methods. Whereas previously only `set_language()` caused the service to actually react to the update (e.g. by reconnecting to a remote service so it an pick up the change), now all these methods do. This change was made as part of a refactor making them all work the same way under the hood.