docs: document VS Code editor indicators (gutter icons, code lens, health checks) (#816)

Documents the gutter icon shapes, code lens health check details, sidebar
health check tree nodes, and expand-all button introduced in
microsoft/aspire#15688.

Co-authored-by: aspire-repo-bot[bot] <268009190+aspire-repo-bot[bot]@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: aspire-repo-bot[bot]

src/frontend/src/content/docs/get-started/aspire-vscode-extension.mdx

@@ -133,6 +133,31 @@ The extension adds an **Aspire** panel to the Activity Bar with a live tree of y
 
 Right-click a resource to start, stop, or restart it, view its logs, run resource-specific commands, or open the dashboard.
 
+Each resource in the tree shows its type, state, health check summary, and exit code (for example, `Project · Running · Health: 1/2`). Resources with health checks display an expandable **Health Checks** group beneath them, with per-check pass/warning/error icons and tooltip descriptions. Use the **Expand all** button on the apphost item to reveal all resources at once.
+
+## Editor indicators
+
+While your app runs, the extension annotates the C# source files for each service directly in the editor.
+
+### Gutter icons
+
+A small icon appears in the editor gutter next to service registrations (for example, `AddProject`, `AddContainer`) to show the current resource state at a glance:
+
+| Icon | Meaning |
+|------|---------|
+| ✓ (green checkmark) | Running and healthy, or completed successfully (exit code 0) |
+| ✓ (pale green checkmark) | Completed — resource exited cleanly |
+| ⚠ (yellow triangle) | Running but unhealthy (health checks failing) |
+| ✕ (red X) | Error — failed, exited with non-zero exit code, or unknown |
+| ⌛ (hourglass) | Starting, stopping, or waiting |
+| ○ (hollow circle) | Not yet started |
+
+The gutter icons use distinct shapes so they do not clash with VS Code breakpoint indicators.
+
+### Code lens
+
+A code lens line appears above each resource registration with a human-readable status such as `Running`, `Starting`, or `Stopped (Exit code: 0)`. When health checks are configured, the code lens also shows a summary count — for example, `Running - (Unhealthy 0/1)` — and hovering it reveals the per-check status as a tooltip.
+
 ## Commands
 
 All commands are available from the Command Palette (<Kbd windows='Ctrl+Shift+P' mac='Cmd+Shift+P' />) under **Aspire**.