Add Alon Elish to MAINTAINERS.md (HolmesGPT#2091)

## Summary

Adds **Alon Elish** ([@alonelish](https://github.com/alonelish),
Robusta) to the active maintainers list in `MAINTAINERS.md`.

## Status

🚧 **Draft — do not merge until the maintainer nomination vote passes.**

Tracking issue: HolmesGPT#2090

Per `GOVERNANCE.md`:
- New maintainers are approved by simple majority vote at a quarterly
Maintainer Meeting.
- This PR will be marked ready-for-review once the vote in HolmesGPT#2090
concludes successfully.

## Eligibility (summary)

- **9 merged PRs in the last 12 months** (≥ 5-PR threshold) — full list
in HolmesGPT#2090.
- Cross-cutting work across FastAPI server, LLM pipeline
(`LLMModelRegistry` pricing, usage tracking), and data-source
integrations.

## Test plan

- [ ] `MAINTAINERS.md` renders correctly on GitHub
(alphabetical-by-affiliation ordering within Robusta group is preserved)
- [ ] Tracking issue HolmesGPT#2090 vote passes


---
_Generated by [Claude
Code](https://claude.ai/code/session_017QaRxLsTqG3NpfEipfarzC)_

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## Summary by CodeRabbit

* **Documentation**
  * Updated project maintainers documentation.

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Signed-off-by: Claude <noreply@anthropic.com>
Co-authored-by: Claude <noreply@anthropic.com>

Author: moshemorad

MAINTAINERS.md

@@ -5,6 +5,7 @@
 | Maintainer          | GitHub ID                                         | Affiliation                                          |
 | --------------------|---------------------------------------------------|------------------------------------------------------|
 | Natan Yellin        | [aantn](https://github.com/aantn)                 | [Robusta](https://github.com/robusta-dev)           |
+| Alon Elish          | [alonelish](https://github.com/alonelish)         | [Robusta](https://github.com/robusta-dev)           |
 | Arik Alon           | [arikalon1](https://github.com/arikalon1)         | [Robusta](https://github.com/robusta-dev)           |
 | Avi Kotlicky        | [Avi-Robusta](https://github.com/Avi-Robusta)     | [Robusta](https://github.com/robusta-dev)           |
 | Pavan Gudiwada      | [pavangudiwada](https://github.com/pavangudiwada) | [Robusta](https://github.com/robusta-dev)           |