docs(issues): add Inbox and issue progress states page

docs/product/issues/inbox/index.mdx

@@ -0,0 +1,97 @@
+---
+title: Inbox
+sidebar_order: 8
+description: >-
+  Learn how to use the Inbox to work through the issues that are closest to
+  being fixed.
+---
+
+<Alert>
+
+Inbox is newly available to organizations with [Seer](/product/ai-in-sentry/seer/) enabled and may change.
+
+</Alert>
+
+The **Inbox** view is where you manage issues you're responsible for. The Inbox sorts your open issues based on their progress toward a fix and shows you actionable next steps for driving the issues forward.
+
+You can find the Inbox by navigating to **Issues > Inbox**. The number next to the link in the inner nav shows you the count of unresolved issues that are `Assigned`, `Diagnosed`, or `Fix Proposed` where you are the assignee or suggested assignee.
+
+## What the Inbox Shows
+
+The Inbox is a two-pane layout (similar to the User Feedback view). The left side shows a list of issues relevant to you, or your teams; the right side includes a preview of the selected issue with relevant details about Seer Autofix and linked PRs, as well as activity and comments.
+
+The list only includes `unresolved` issues in the categories Seer can work on: error, mobile, frontend, database query, HTTP client, and configuration. Resolved and archived issues never appear, and neither do categories outside that list, such as uptime outages and cron failures.
+
+### Issue Progress
+
+An issue's progress is derived from the history of activity on an issue. Issues are grouped by their progress into collapsible sections, sorted so that the most recently progressed issues closest to being fixed are at the top of the list.
+
+Progress descriptions are like a ladder, and the highest applicable description is applied to the issue.
+
+| Section          | Condition                                                                              |
+| ---------------- | -------------------------------------------------------------------------------------- |
+| `Fix Proposed`   | At least one open pull request references the issue (for example, `Fixes SENTRY-123`). |
+| `Diagnosed`      | Seer identified a root cause.                                                          |
+| `Assigned`       | The issue is assigned to, or suggested for, you or your teams.                         |
+| `Fix Applied`    | A resolving pull request has been merged, but the issue isn't resolved yet.            |
+
+Every issue starts with the progress description `Identified`. If an issue is `Identified`, nothing has happened to it yet, so it has no assignee, root cause, or pull request. `Identified` issues are not surfaced in the Inbox.
+
+Each section header shows a corresponding progress marker and a count of matching issues. Click a section's header to expand or collapse it. Each section loads 10 issues at a time; use **Show more** at the bottom of a section to load additional issues.
+
+An issue moves between these sections as work happens to progress the issue toward a fix. See [How Progress Changes](#how-progress-changes) for the full set of events that advance or roll back an issue's progress.
+
+### Filters
+
+The toggle at the top of the list controls which issues are shown in the list:
+
+- **Me**: Issues assigned to you, or suggested for you.
+- **My Teams**: Issues assigned to or suggested for any team you're on.
+- **All**: Every assigned issue in the organization.
+
+Learn more about automated assignment by checking out [ownership rules](/product/issues/ownership-rules/) and [suspect commits](/product/issues/suspect-commits/).
+
+### The Preview Pane
+
+The preview pane is limited to only the details of an issue required to decide what to do next without leaving the page. Opening an issue in the preview marks it as seen. Click the open icon next to the title to go to the full [Issue Details](/product/issues/issue-details/) page.
+
+The preview includes:
+
+- **Actions**: Seer actions such as **Find Root Cause**, **Make a Plan**, **Write a Code Fix**, **Create PR**, and **Continue in Seer**, which reflect where Autofix has gotten to on this issue. If Seer isn't available for the issue, you get the standard issue actions (resolve, archive, and so on) instead.
+- **Priority and assignee**: Change the issue's [priority](/product/issues/issue-priority/) or reassign it in place.
+- **Linked pull requests**: Any pull requests that reference the issue.
+- **Autofix summary**: Seer's root cause, plan, and proposed code changes, when they exist.
+- **Activity**: The issue's activity feed, where you can leave a comment and tag teammates with `@` or teams with `#`.
+
+## How Progress Changes
+
+Progress is recalculated as things happen to the issue:
+
+| What happens                                                       | Effect on progress                                                                 |
+| ------------------------------------------------------------------ | ---------------------------------------------------------------------------------- |
+| The issue is assigned                                              | Advances to at least `Assigned`.                                                   |
+| The issue is unassigned                                            | Falls back to `Identified`, unless a root cause or pull request keeps it higher.  |
+| Seer identifies a root cause                                       | Advances to at least `Diagnosed`.                                                  |
+| A resolving pull request is opened or reopened                     | Advances to `Fix Proposed`.                                                        |
+| The last open pull request is closed or unlinked                   | Falls back to `Diagnosed`, `Assigned`, or `Identified`.                            |
+| A resolving pull request is merged                                 | Advances to `Fix Applied`.                                                         |
+| Anything else, while the issue is open and already `Fix Applied`   | Stays `Fix Applied`.                                                               |
+| The issue is resolved or archived                                  | The issue closes and progress is no longer derived.                            |
+| A closed issue is unresolved, regresses, or escalates              | The issue reopens and its progress is recalculated.                                |
+
+A few behaviors are worth calling out:
+
+- Assignment survives closing and reopening an issue.
+- Manually reopening an issue preserves the root cause Seer identified.
+- A regression clears the root cause before recalculating progress.
+- An open resolving pull request survives closing the issue and can restore `Fix Proposed` when the issue reopens.
+
+For example, an issue that gets a resolving pull request, has it merged, and then gets resolved in a commit reaches `Fix Proposed`, then `Fix Applied`, then closes. If it later regresses, it reopens at `Identified`, because the regression cleared the root cause and no higher condition still applies.
+
+### Autofix and Progress
+
+Autofix steps move the issue along, but only up to a point. Recording a root cause moves an issue to `Diagnosed`; writing a plan and generating code changes don't advance it further on their own. It's the resolving pull request that moves the issue to `Fix Proposed`.
+
+If that pull request is closed without merging, progress falls back, usually to `Diagnosed`, since Autofix recorded a root cause on the way there, or to `Assigned` or `Identified` if it didn't. A merged pull request behaves differently: it moves the issue to `Fix Applied`, which sticks for as long as the issue stays open.
+
+When an issue has more than one resolving pull request, progress reflects whether _any_ of them is still open. Closing one while another remains open leaves the issue at `Fix Proposed`. Only when the last open pull request closes without merging does progress fall back.

docs/product/issues/index.mdx

@@ -54,13 +54,15 @@ Sentry creates issues for more than just errors. The **Issues** page sidebar gro
 From the **Issues** page, you can begin to triage. The page is organized into tabs, each corresponding to a filtered list of issues, and these different lists help you with triaging:
 
 - All Unresolved (`is:unresolved`): All unresolved issues, including issues that need review.
-- For Review (`is:unresolved is:for_review`). Also called **Review List**,  for-review issues are a subset of all unresolved issues and can include new issues or regressions that haven't been reviewed yet.
+- For Review (`is:unresolved is:for_review`). Also called **Review List**, for-review issues are a subset of all unresolved issues and can include new issues or regressions that haven't been reviewed yet.
 - Regressed (`is:regressed`): All regressed issues; resolved issues that have come up again.
 - Archived (`is:archived`): All archived issues.
 - Escalating (`is:escalating`): All escalating issues; previously archived issues that have exceeded their forecasted event volume.
 
 Learn more about triaging issues and their different states in [Issue States and Triage](/product/issues/states-triage/).
 
+If your organization has Seer, the [**Inbox**](/product/issues/inbox/) offers a different way to triage: it groups the issues assigned to you by how close they are to being fixed, so you can start with the ones that need the least work to finish.
+
 ## How to Sort Issues
 
 Change how issues are sorted in the issues stream by selecting from the sort dropdown: