REQUEST: New membership for semx

### GitHub Username

@semx

### Organization you are requesting membership in

kubernetes

### Requirements

- [x] I have reviewed the [community membership guidelines](https://git.k8s.io/community/community-membership.md)
- [x] I have [enabled 2FA on my GitHub account](https://github.com/settings/security)
- [x] I have subscribed to the [kubernetes dev e-mail list](https://groups.google.com/a/kubernetes.io/group/dev)
- [x] I am actively contributing to 1 or more Kubernetes subprojects
- [x] I have two sponsors that meet the sponsor requirements listed in the community membership guidelines
- [x] I have spoken to my sponsors ahead of this application, and they have agreed to sponsor my application
- [x] I have verified that my sponsors are from different member companies
- [x] I have verified that my sponsors are a reviewer or an approver in at least one OWNERS file within one of the Kubernetes GitHub organizations (excluding the contributor-playground)
- [x] **SUGGESTED:** Ensure your affiliation in gitdm is up to date
- [x] **SUGGESTED:** Ensure your affiliation in openprofile.dev is up to date

### Sponsor 1

@jpbetz

### Sponsor 2

@jackfrancis

### List of contributions to the Kubernetes project

I have been contributing across SIG API Machinery and SIG Autoscaling, mostly small correctness fixes with regression tests.

**Merged, kubernetes/kubernetes (SIG API Machinery):**
- #140459 — Quantity.String() dropped the suffix for DecimalSI values above 10^18
- #141169 — use Sign() to reject negative quantities in validateBasicResource
- #141201 — regression test for the Scale(MinInt32).infScale() sign edge (reviewed & approved by @jpbetz)

**Merged, kubernetes/autoscaler (addon-resizer, SIG Autoscaling):**
- #10112 — update golang.org/x dependencies (reachable CVEs)
- #10113 — add a build/test CI workflow (first CI on the branch)
- #10114 — fix go vet findings

(All three addon-resizer PRs reviewed & approved by @jackfrancis.)

**Open, under review (SIG API Machinery):**
- #141390 — fix strategic-merge conflict detection for primitive-list directives
- #141204 — MicroTime: accept flexible fractional-second precision
- #140592 — fix CEL map-list merge of duplicate new keys
- #140462 — fix label Gt/Lt selectors dropping values above int64

**Issue participation:**
- Active on the SIG API Machinery Quantity int64-overflow burndown (#141166), and authored the linked bug issues for several of the fixes above.

SIG involvement: SIG API Machinery (primary) and SIG Autoscaling.

Start by reviewing the community membership guidelines and the applicant's checked requirements, sponsors, and contribution list. Verify the stated sponsorship and eligibility details against the Kubernetes organization membership process; done means the membership request is approved or a specific missing requirement is identified.

Written by the indexing model from the issue text.