Merge rate limits into billing page and add concurrent builds limit

- Move rate limit rows into the Plans table with tooltip explanations
- Move concurrency add-on pricing ($500/month) into a tooltip
- Add concurrent builds limit (20 for Hobby/Pro, Custom for Enterprise)
- Remove standalone rate-limits page and its nav entry

Author: beran-t

docs.json

@@ -119,7 +119,6 @@
               "docs/sandbox/pty",
               "docs/sandbox/ssh-access",
               "docs/sandbox/connect-bucket",
-              "docs/sandbox/rate-limits",
               "docs/sandbox/secured-access",
               "docs/sandbox/ip-tunneling",
               "docs/sandbox/custom-domain"

docs/billing.mdx

@@ -15,13 +15,12 @@ E2B uses [usage-based pricing](#usage-based-pricing) - you pay only for what you
 | **Base price** | $0/month | $150/month | Custom |
 | **Free credits** | $100 (one-time) | $100 (one-time) | Custom |
 | **Max session length** | 1 hour | 24 hours | Custom |
-| **Concurrent sandboxes** | 20 | 100 - 1,100 | 1,100+ |
-
-<Note>
-Pro plan includes 100 concurrent sandboxes. Higher concurrency up to 1,100 is available as an [add-on](https://e2b.dev/dashboard?tab=billing) for $500/month.
-</Note>
-
-Plans have different [API rate limits](/docs/sandbox/rate-limits).
+| **<Tooltip tip="Number of sandboxes running at the same time.">Concurrent sandboxes</Tooltip>** | 20 | <Tooltip tip="Includes 100 concurrent sandboxes. Higher concurrency up to 1,100 is available as an add-on for $500/month.">100 - 1,100</Tooltip> | 1,100+ |
+| **<Tooltip tip="Number of template builds running at the same time.">Concurrent builds</Tooltip>** | 20 | 20 | Custom |
+| **<Tooltip tip="Applies to lifecycle and management operations such as sandbox create, kill, update, and list.">Sandbox API rate limit</Tooltip>** | 20,000 / 30s | 20,000 / 30s | Custom |
+| **<Tooltip tip="Applies to operations within running sandboxes such as running code, listing files, and running commands. Enforced per IP address.">Sandbox operations rate limit</Tooltip>** | 40,000 / 60s | 40,000 / 60s | Custom |
+| **<Tooltip tip="How quickly you can create new sandboxes.">Sandbox creation rate</Tooltip>** | 1 / sec | 5 / sec | Custom |
+| **<Tooltip tip="Maximum outbound network connections from a single sandbox.">Egress connections</Tooltip>** | 2,500 | 2,500 | Custom |
 
 To upgrade your plan or purchase add-ons, visit the [dashboard billing tab](https://e2b.dev/dashboard?tab=billing). For Enterprise plans, [contact sales](mailto:enterprise@e2b.dev).