Assorted copy & URL updates (#14222)

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<!-- Use this checklist to make sure your PR is ready for merge. You may delete any sections you don't need. -->

## DESCRIBE YOUR PR
This PR makes two documentation updates:
1.  Removes "With insights," from the first paragraph of the Insights overview page (`docs/product/insights/overview/index.mdx`) to eliminate redundancy with the page's H2 and description.
2.  Adds content to the "Agent Pipelines vs Direct LLM Calls" callout on the Agents dashboard page (`docs/product/insights/agents/dashboard.mdx`). This provides important context on the difference between AI pipelines and direct LLM calls, and includes a link to relevant manual instrumentation documentation.

## IS YOUR CHANGE URGENT?  

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- [ ] Urgent deadline (GA date, etc.): <!-- ENTER DATE HERE -->
- [ ] Other deadline: <!-- ENTER DATE HERE -->
- [X] None: Not urgent, can wait up to 1 week+

## SLA

- Teamwork makes the dream work, so please add a reviewer to your PRs.
- Please give the docs team up to 1 week to review your PR unless you've added an urgent due date to it.
Thanks in advance for your help!

## PRE-MERGE CHECKLIST

*Make sure you've checked the following before merging your changes:*

- [X] Checked Vercel preview for correctness, including links
- [ ] PR was reviewed and approved by any necessary SMEs (subject matter experts)
- [ ] PR was reviewed and approved by a member of the [Sentry docs team](https://github.com/orgs/getsentry/teams/docs)

## LEGAL BOILERPLATE

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Look, I get it. The entity doing business as "Sentry" was incorporated in the State of Delaware in 2015 as Functional Software, Inc. and is gonna need some rights from me in order to utilize my contributions in this here PR. So here's the deal: I retain all rights, title and interest in and to my contributions, and by keeping this boilerplate intact I confirm that

---------

Co-authored-by: Alex Krawiec <alex.krawiec@sentry.io>

Author: jaffrepaul

docs/product/insights/overview/index.mdx

@@ -4,7 +4,7 @@ sidebar_order: 50
 description: "With insights, you can track, analyze, and debug your application's performance. Sentry helps you identify performance opportunities and trace issues back to poorly performing code."
 ---
 
-With insights, Sentry tracks application performance, measuring metrics like throughput and latency, and displaying the impact of errors across multiple services. Sentry captures [distributed traces](/product/sentry-basics/tracing/distributed-tracing/) consisting of [transactions](/product/insights/overview/transaction-summary/#what-is-a-transaction) and spans to measure individual services and operations within those services.
+Sentry tracks application performance, measuring metrics like throughput and latency, and displaying the impact of errors across multiple services. Sentry captures [distributed traces](/product/sentry-basics/tracing/distributed-tracing/) consisting of multiple [spans](/product/explore/trace-explorer/#spans) to measure individual services and operations within those services.
 
 <Alert>
 

docs/product/releases/setup/index.mdx

@@ -71,7 +71,7 @@ Make sure you have a [token](/cli/configuration/) properly configured.
 
 Typically, a release = a deployment, but if you have several environments in which you want to deploy a release, this step also allows you to create those deployments individually.
 
-You can also use our [API](/api/releases/create-a-new-deploy-for-an-organization/) to create a deploy.
+You can also use our [API](/api/releases/create-a-deploy/) to create a deploy.
 
 When you notify Sentry that you've deployed a release to a new environment, we can automatically send an email to Sentry users who have committed to the release being deployed.