New data retention policy page (#14661)

## DESCRIBE YOUR PR
Related to the logs GA August 26th, we're adding a specific docs page
for our data retention policies. They're now broken out by data type and
plan type.

Preview:
https://sentry-docs-git-new-data-retention-doc.sentry.dev/security-legal-pii/security/data-retention-periods/

## IS YOUR CHANGE URGENT?  

Help us prioritize incoming PRs by letting us know when the change needs
to go live.
- [x] Urgent deadline (GA date, etc.): August 26th
- [ ] Other deadline: <!-- ENTER DATE HERE -->
- [ ] 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:*

- [ ] 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)

---------

Co-authored-by: Shannon Anahata <[email protected]>

Author: sfanahata

docs/security-legal-pii/security/data-retention-periods.mdx

@@ -0,0 +1,52 @@
+---
+title: "Data Retention Periods"
+sidebar_order: 15
+description: "Learn about Sentry's data retention periods for different data types and plan tiers."
+---
+
+## Overview
+
+Sentry retains different types of data for varying periods based on your plan tier and the specific data type. The below table outlines the retention periods for data types across our Developer, Team, and Business plans.
+
+By default, new account trials are granted Team plan retention. If you are trialing from a paid plan type, you will have the same retention as that plan for any data ingested during the trial.  
+
+## Default Data Retention by Plan
+
+| Data Type | Developer | Team | Business |
+|-----------|-----------|------|----------|
+| [Errors](/concepts/key-terms/enrich-data/) | 30 days | 90 days | 90 days |
+| [Logs](/product/explore/logs/) | 30 days | 30 days | 30 days |
+| [Spans/Transactions](/concepts/key-terms/tracing/distributed-tracing/) | 30 days | 90 days | 90 days + 13 months sampled |
+| [Session Replays](/product/explore/session-replay/web/) | 30 days | 90 days | 90 days |
+| [Profiles](/product/explore/profiling/) | 30 days | 90 days | 90 days |
+| [Crons](/product/crons/) | 30 days | 30 days | 30 days |
+| [Uptime](/product/monitoring/) | 30 days | 90 days | 90 days |
+| [Attachments](/product/issues/issue-details/attachments/) | 30 days | 90 days | 90 days |
+
+<Alert>
+Starting November 2025, Team and Business plans will move from the current 90 day retention period for spans, transactions, and profiles to 30 days. **Exception:** If you are on a [Team or Business plan](https://sentry.io/settings/billing/overview/) that uses transaction-based billing, transaction retention will stay at 90 days, and sampled retention of spans data will not apply.
+</Alert>
+
+## Sampled Retention for Business Plans
+
+Business plan customers receive extended retention for spans data through our sampled retention feature. This provides up to:
+
+- **Full fidelity data**: 90 days of complete span data
+- **Sampled data**: 13 months of downsampled span data 
+
+13 month downsampled data is a percentage of span data. Sampled retention is currently only available for span data.
+
+## Data Retention Details
+
+### When Retention is Applied
+
+Retention periods are applied at the time data is ingested, based on the then-current plan. This means plan upgrades or downgrades affect retention for new data only; existing data retains its original retention period.
+
+## Extended Retention
+
+When data reaches the end of its retention period, it can no longer be accessed. If you need to retain data beyond the standard retention period, consider:
+
+- Upgrading to a plan with longer retention
+- Contacting support for enterprise retention options
+
+Reference our [security policy](https://sentry.io/security/) for information about data deletion.