feat: cherry-pick PR #1503 and #1557 into release/0.8

[joanestebanr]

🔄 Changes Summary

Cherry-pick of #1503 and #1557 into `release/0.8`

#1503 - Treat already-monitored GER tx as expected

• Treats `ErrAlreadyExists` from `ethtxmanager` as expected behavior (not an error) in `submitTransaction`
• Updates `zkevm-ethtx-manager` from v0.2.17 to v0.2.18

#1557 - Adjust REST timeouts

• Increases `defaultDBQueryTimeout` from `60s` to `5m`
• Increases REST server `ReadTimeout` and `WriteTimeout` from `2s` to `5m`
• Motivation: previous values were too short for slow queries and long-running REST requests (e.g. aggchain proof generation can take up to 1h)

⚠️ Breaking Changes

None

📋 Config Updates

• `defaultDBQueryTimeout`: `60s` → `5m`
• `REST.ReadTimeout` / `REST.WriteTimeout`: `2s` → `5m`

✅ Testing

• 🤖 Automatic: Unittest

🐞 Issues

• Related: feat: Treat already-monitored GER tx as expected #1490 #1503, fix: treat an existing monitored GER update tx as expected (#1479) #1490, feat: adjust REST timeouts #1557, bug: adjust default timeout for aggkit #1540

🔗 Related PRs

• feat: Treat already-monitored GER tx as expected #1490 #1503 (cherry-pick against `develop`)
• feat: adjust REST timeouts #1557 (cherry-pick against `develop`)

🤖 Generated with Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud