Move L2 gas limit operational docs from maintain_sequencer.md into

upgrades.md under the v10→v11 section and remove the standalone file

Author: avilagaston9

docs/SUMMARY.md

@@ -73,7 +73,6 @@
   - [Blockscout for ethrex L2](./l2/interacting/blockscout.md)
   - [L2 Hub](./l2/interacting/l2_hub.md)
   - [Shared Bridge](./l2/interacting/shared_bridge.md)
-  - [Maintain the sequencer](./l2/interacting/maintain_sequencer.md)
 - [Fundamentals](./l2/fundamentals/README.md)
   - [State diffs](./l2/fundamentals/state_diffs.md)
   - [Block vs StateDiff](./l2/fundamentals/block_vs_state_diff_measurements.md)

docs/l2/deployment/upgrades.md

@@ -104,3 +104,21 @@ The contract must not be unpaused until `l2GasLimit` is set to a valid value. Ot
 #### CLI flag removed
 
 The `--block-producer.block-gas-limit` flag has been removed. The sequencer now reads the gas limit from the `CommonBridge` contract on startup. Update any scripts or deployment configurations that use this flag.
+
+#### Viewing the current gas limit
+
+```shell
+rex call <BRIDGE_ADDRESS> "l2GasLimit()" --rpc-url <L1_RPC_URL>
+```
+
+#### Updating the gas limit
+
+Only the bridge owner can update the gas limit:
+
+```shell
+rex send <BRIDGE_ADDRESS> "setL2GasLimit(uint256)" <NEW_GAS_LIMIT> \
+  --private-key <OWNER_PRIVATE_KEY> \
+  --rpc-url <L1_RPC_URL>
+```
+
+After updating the on-chain value, restart the sequencer for it to take effect. Until the restart, the sequencer continues using the previous gas limit, which may cause a temporary mismatch with the on-chain value.