[Develop Docs] Clean up "SDK Development" Sidebar (#11542)

Organize the information in the "SDK Development" section of the develop docs better.

develop-docs/application/feedback-architecture.mdx

@@ -15,12 +15,12 @@ When broken down, there are **5** ways to create feedback in our system 😵‍
 `FeedbackCreationSource(Enum)` in [create_feedback.py](https://github.com/getsentry/sentry/blob/2b642e149c79b251e1c2f4339fc73d656347d74e/src/sentry/feedback/usecases/create_feedback.py#L33-L33).
 The 4 ways _clients_ can create feedback are:
 
-`NEW_FEEDBACK_ENVELOPE`: [The new format](https://develop.sentry.dev/sdk/envelopes/#full-examples) created by the Replay team when adding
+`NEW_FEEDBACK_ENVELOPE`: [The new format](https://develop.sentry.dev/sdk/data-model/envelopes/#full-examples) created by the Replay team when adding
 the [User Feedback Widget](https://docs.sentry.io/product/user-feedback/#user-feedback-widget)
 to the JavaScript SDK. It allows adding more information, for example tags,
 release, url, etc.
 
-`USER_REPORT_ENVELOPE`: [The older format](https://develop.sentry.dev/sdk/envelopes/#user-feedback) with name/email/comments, that requires
+`USER_REPORT_ENVELOPE`: [The older format](https://develop.sentry.dev/sdk/data-model/envelope-items/#user-feedback) with name/email/comments, that requires
 `event_id` to link a Sentry error event.
 
 `USER_REPORT_DJANGO_ENDPOINT`: [The deprecated Web API](https://docs.sentry.io/api/projects/submit-user-feedback/)
@@ -41,7 +41,7 @@ which
 
 ## Feedback events
 
-The new and preferred way to send feedback from the SDK is in an [event envelope](https://develop.sentry.dev/sdk/envelopes/#full-examples).
+The new and preferred way to send feedback from the SDK is in an [event envelope](https://develop.sentry.dev/sdk/data-model/envelopes/#full-examples).
 The format is the same as error events, except the `type` header = `"feedback"`. While
 user reports have an associated event, **new feedback _is_ an event**. This
 offers 2 improvements:
@@ -84,7 +84,7 @@ In Relay v24.5.1, we migrated feedback to its own kafka topic + consumer,
 ### Attachments
 
 We only use attachments for the widget’s screenshot feature, which allows users
-to submit **at most 1 screenshot per feedback**. Attachments are another [item type](https://develop.sentry.dev/sdk/envelopes/#attachment)
+to submit **at most 1 screenshot per feedback**. Attachments are another [item type](https://develop.sentry.dev/sdk/data-model/envelopes/#attachment)
 in an envelope.
 
 - SDK v8.0.0+, Relay v24.5.1+: Sends the feedback and attachment items in the same envelope.
@@ -139,7 +139,7 @@ Simplified diagram:
 
 ### Envelopes
 
-User reports are also sent to Relay in [envelope format](https://develop.sentry.dev/sdk/envelopes/#user-feedback).
+User reports are also sent to Relay in [envelope format](https://develop.sentry.dev/sdk/data-model/envelope-items/#user-feedback).
 **This item type is misleadingly called “user feedback” in some of our docs, but the
 item header will read `"user_report"`.**
 

develop-docs/application/issue-platform/index.mdx

@@ -143,7 +143,7 @@ The most current version of this schema is documented here:
   Schema
 </Link>
 
-The event schema should match the <Link to="/sdk/event-payloads">Sentry event schema</Link>. Any fields/interfaces defined here can be passed along with your event. It's best to fill in as many of these as makes sense for your issue type.
+The event schema should match the <Link to="/sdk/data-model/event-payloads/">Sentry event schema</Link>. Any fields/interfaces defined here can be passed along with your event. It's best to fill in as many of these as makes sense for your issue type.
 
 There's a minimum set of fields which should be included:
 

develop-docs/application/transaction-clustering/index.mdx

@@ -12,7 +12,7 @@ In terms of technical implementation, it is similar to [Data Scrubbing](/pii/).
 ## The Problem
 
 In our [Performance](https://docs.sentry.io/product/performance/) product, transactions are grouped by their name
-(the [`event.transaction`](/sdk/event-payloads/#optional-attributes) field).
+(the [`event.transaction`](/sdk/data-model/event-payloads/#optional-attributes) field).
 This works well as long as the cardinality of distinct transaction names that the SDK sends is low, for example
 by using the [route of a web framework](https://docs.sentry.io/platforms/javascript/guides/react/configuration/integrations/react-router/) as the transaction name.