…onfig lifecycle (openedx#1897)"

This reverts commit 59113b0.

Reverts the following two commits:

- 59113b0 feat: move discussion topic prefetch from trigger to widget
  config lifecycle (openedx#1897)
- 0664dc3 feat: decouple notifications panel using widget registry
  mechanism (openedx#1885)

Co-Authored-By: Claude <noreply@anthropic.com>

…t it to TypeScript

The courseware sidebar provider becomes TypeScript, and the two patterns in
it that predate React Query go with the conversion instead of being typed
around. The context was created with a default object, so a consumer rendered
outside `SidebarProvider` got empty values instead of an error; it is now
`createContext<SidebarContextValue | null>(null)` with a `useSidebarContext()`
hook that throws outside the provider. The provider ran every widget's
`prefetch` from an effect that read the merged course metadata through a ref,
PR #1897's fix for the effect firing twice as the two metadata models settled
in separate batches, approved then as a workaround pending React Query.

The one `prefetch` user, the discussions widget, now loads its topics as a
query observer in a `Provider` component, mounted by the framework for every
enabled widget inside `SidebarContext`, with `enabled` set only when the
discussions MFE is configured and the course has a discussion tab. An observer
fetches on mount and on key change, not when the metadata it reads
re-renders, so one sidebar mount is one topics request and a metadata write
is none. The query definition is a `queryOptions` object,
`discussionTopicsQuery`, shared with the tests and with #2087's reader hook;
its bridge `meta` stays until that layer converts the three `useModel`
readers. The effect, `courseMetaRef`, the duplicated merge and the `prefetch`
field of the widget contract are gone.

The widget contract gets named types in `SidebarContext.ts`: `SidebarWidget`,
`SidebarWidgetContext` (`course: CourseHomeMeta & CoursewareMeta`,
`unit: Partial<DiscussionTopic>`, the line #2087 changes) and
`SidebarContextValue`. `CoursewareMeta` and `DiscussionTopic` are declared
beside their queries. Both built-in widget configs are TypeScript and declared
against `SidebarWidget`; the upgrade widget's context module converts with
them. The sidebar README's contract sections point at the declarations
instead of restating them, and the prefetch section describes the `Provider`
observer.

Tests: `DiscussionsProvider.test.tsx` measures the observer's gates as
requests and pins that a course-metadata write does not refetch the topics;
`SidebarContext.test.tsx` covers the hook's throw; `LockPaywall`,
`SequenceNavigation` and `SequenceNavigationTabs` render their context
consumer under a provider, which the default value had let them skip.

BREAKING CHANGE: the `prefetch` field of a `SIDEBAR_WIDGETS` entry is no
longer called. A widget that loaded data through it loads it in its
`Provider` component with `useQuery` and `enabled`; see "Loading widget data"
in src/courseware/course/sidebar/README.md. `useContext(SidebarContext)`
returns `null` outside `SidebarProvider`; read the context with
`useSidebarContext()` from src/courseware/course/sidebar/SidebarContext.ts.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

…t it to TypeScript

The courseware sidebar provider becomes TypeScript, and the two patterns in
it that predate React Query go with the conversion instead of being typed
around. The context was created with a default object, so a consumer rendered
outside `SidebarProvider` got empty values instead of an error; it is now
`createContext<SidebarContextValue | null>(null)` with a `useSidebarContext()`
hook that throws outside the provider. The provider ran every widget's
`prefetch` from an effect that read the merged course metadata through a ref,
PR #1897's fix for the effect firing twice as the two metadata models settled
in separate batches, approved then as a workaround pending React Query.

The one `prefetch` user, the discussions widget, now loads its topics as a
query observer in a `Provider` component, mounted by the framework for every
enabled widget inside `SidebarContext`, with `enabled` set only when the
discussions MFE is configured and the course has a discussion tab. An observer
fetches on mount and on key change, not when the metadata it reads
re-renders, so one sidebar mount is one topics request and a metadata write
is none. The query definition is a `queryOptions` object,
`discussionTopicsQuery`, shared with the tests and with #2087's reader hook;
its bridge `meta` stays until that layer converts the three `useModel`
readers. The effect, `courseMetaRef`, the duplicated merge and the `prefetch`
field of the widget contract are gone.

The widget contract gets named types in `SidebarContext.ts`: `SidebarWidget`,
`SidebarWidgetContext` (`course: CourseHomeMeta & CoursewareMeta`,
`unit: Partial<DiscussionTopic>`, the line #2087 changes) and
`SidebarContextValue`. `CoursewareMeta` and `DiscussionTopic` are declared
beside their queries. Both built-in widget configs are TypeScript and declared
against `SidebarWidget`; the upgrade widget's context module converts with
them. The sidebar README's contract sections point at the declarations
instead of restating them, and the prefetch section describes the `Provider`
observer.

Tests: `DiscussionsProvider.test.tsx` measures the observer's gates as
requests and pins that a course-metadata write does not refetch the topics;
`SidebarContext.test.tsx` covers the hook's throw; `LockPaywall`,
`SequenceNavigation` and `SequenceNavigationTabs` render their context
consumer under a provider, which the default value had let them skip.

BREAKING CHANGE: the `prefetch` field of a `SIDEBAR_WIDGETS` entry is no
longer called. A widget that loaded data through it loads it in its
`Provider` component with `useQuery` and `enabled`; see "Loading widget data"
in src/courseware/course/sidebar/README.md. `useContext(SidebarContext)`
returns `null` outside `SidebarProvider`; read the context with
`useSidebarContext()` from src/courseware/course/sidebar/SidebarContext.ts.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

…t it to TypeScript

The courseware sidebar provider becomes TypeScript, and the two patterns in
it that predate React Query go with the conversion instead of being typed
around. The context was created with a default object, so a consumer rendered
outside `SidebarProvider` got empty values instead of an error; it is now
`createContext<SidebarContextValue | null>(null)` with a `useSidebarContext()`
hook that throws outside the provider. The provider ran every widget's
`prefetch` from an effect that read the merged course metadata through a ref,
PR #1897's fix for the effect firing twice as the two metadata models settled
in separate batches, approved then as a workaround pending React Query.

The one `prefetch` user, the discussions widget, now loads its topics as a
query observer in a `Provider` component, mounted by the framework for every
enabled widget inside `SidebarContext`, with `enabled` set only when the
discussions MFE is configured and the course has a discussion tab. An observer
fetches on mount and on key change, not when the metadata it reads
re-renders, so one sidebar mount is one topics request and a metadata write
is none. The query definition is a `queryOptions` object,
`discussionTopicsQuery`, shared with the tests and with #2087's reader hook;
its bridge `meta` stays until that layer converts the three `useModel`
readers. The effect, `courseMetaRef`, the duplicated merge and the `prefetch`
field of the widget contract are gone.

The widget contract gets named types in `SidebarContext.ts`: `SidebarWidget`,
`SidebarWidgetContext` (`course: CourseHomeMeta & CoursewareMeta`,
`unit: Partial<DiscussionTopic>`, the line #2087 changes) and
`SidebarContextValue`. `CoursewareMeta` and `DiscussionTopic` are declared
beside their queries. Both built-in widget configs are TypeScript and declared
against `SidebarWidget`; the upgrade widget's context module converts with
them. The sidebar README's contract sections point at the declarations
instead of restating them, and the prefetch section describes the `Provider`
observer.

Tests: `DiscussionsProvider.test.tsx` measures the observer's gates as
requests and pins that a course-metadata write does not refetch the topics;
`SidebarContext.test.tsx` covers the hook's throw; `LockPaywall`,
`SequenceNavigation` and `SequenceNavigationTabs` render their context
consumer under a provider, which the default value had let them skip.

The provider's first render now reads `useWindowSize().width ?? window.innerWidth`
instead of an undefined width. That fixes a bug present since #1885: on a
narrow viewport the first render seeded the sidebar closed, and the mobile
branches of the sidebar hooks never corrected it, so a panel a learner had
opened did not restore after a refresh. Desktop reaches the same state as
before, without a transient outline render and two storage writes per load.

BREAKING CHANGE: the `prefetch` field of a `SIDEBAR_WIDGETS` entry is no
longer called. A widget that loaded data through it loads it in its
`Provider` component with `useQuery` and `enabled`; see "Loading widget data"
in src/courseware/course/sidebar/README.md. `useContext(SidebarContext)`
returns `null` outside `SidebarProvider`; read the context with
`useSidebarContext()` from src/courseware/course/sidebar/SidebarContext.ts.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

…t it to TypeScript (#2113)

The courseware sidebar provider becomes TypeScript, and the two patterns in
it that predate React Query go with the conversion instead of being typed
around. The context was created with a default object, so a consumer rendered
outside `SidebarProvider` got empty values instead of an error; it is now
`createContext<SidebarContextValue | null>(null)` with a `useSidebarContext()`
hook that throws outside the provider. The provider ran every widget's
`prefetch` from an effect that read the merged course metadata through a ref,
PR #1897's fix for the effect firing twice as the two metadata models settled
in separate batches, approved then as a workaround pending React Query.

The one `prefetch` user, the discussions widget, now loads its topics as a
query observer in a `Provider` component, mounted by the framework for every
enabled widget inside `SidebarContext`, with `enabled` set only when the
discussions MFE is configured and the course has a discussion tab. An observer
fetches on mount and on key change, not when the metadata it reads
re-renders, so one sidebar mount is one topics request and a metadata write
is none. The query definition is a `queryOptions` object,
`discussionTopicsQuery`, shared with the tests and with #2087's reader hook;
its bridge `meta` stays until that layer converts the three `useModel`
readers. The effect, `courseMetaRef`, the duplicated merge and the `prefetch`
field of the widget contract are gone.

The widget contract gets named types in `SidebarContext.ts`: `SidebarWidget`,
`SidebarWidgetContext` (`course: CourseHomeMeta & CoursewareMeta`,
`unit: Partial<DiscussionTopic>`, the line #2087 changes) and
`SidebarContextValue`. `CoursewareMeta` and `DiscussionTopic` are declared
beside their queries. Both built-in widget configs are TypeScript and declared
against `SidebarWidget`; the upgrade widget's context module converts with
them. The sidebar README's contract sections point at the declarations
instead of restating them, and the prefetch section describes the `Provider`
observer.

Tests: `DiscussionsProvider.test.tsx` measures the observer's gates as
requests and pins that a course-metadata write does not refetch the topics;
`SidebarContext.test.tsx` covers the hook's throw; `LockPaywall`,
`SequenceNavigation` and `SequenceNavigationTabs` render their context
consumer under a provider, which the default value had let them skip.

The provider's first render now reads `useWindowSize().width ?? window.innerWidth`
instead of an undefined width. That fixes a bug present since #1885: on a
narrow viewport the first render seeded the sidebar closed, and the mobile
branches of the sidebar hooks never corrected it, so a panel a learner had
opened did not restore after a refresh. Desktop reaches the same state as
before, without a transient outline render and two storage writes per load.

BREAKING CHANGE: the `prefetch` field of a `SIDEBAR_WIDGETS` entry is no
longer called. A widget that loaded data through it loads it in its
`Provider` component with `useQuery` and `enabled`; see "Loading widget data"
in src/courseware/course/sidebar/README.md. `useContext(SidebarContext)`
returns `null` outside `SidebarProvider`; read the context with
`useSidebarContext()` from src/courseware/course/sidebar/SidebarContext.ts.

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>