fix(agentex-ui): bump sharp 0.34.3 -> 0.35.3 (GHSA-f88m-g3jw-g9cj) (#371)

## Summary
Remediates **GHSA-f88m-g3jw-g9cj** (HIGH) in `sharp`, reported by Trivy
against the `agentex-ui` image.

`sharp` < 0.35.0 inherits four libvips vulnerabilities:
- CVE-2026-33327
- CVE-2026-33328
- CVE-2026-35590
- CVE-2026-35591

`sharp` 0.35.0+ bundles the fixed **libvips 8.18.3**.

| | Before | After |
|---|---|---|
| `sharp` | 0.34.3 | **0.35.3** |
| bundled libvips (`@img/sharp-libvips-*`) | 1.2.0 (libvips 8.17.x) |
**1.3.2 (libvips 8.18.3)** |

## Change
`sharp` is a **transitive** `optionalDependency` of `next@15.5.18`
(declared `^0.34.3`, which caps at `<0.35.0`). It is not a direct
dependency and is not imported by application code. It is pinned via the
existing npm `overrides` block in `agentex-ui/package.json`:

```json
"overrides": {
  "sharp": "^0.35.0"
}
```

`^0.35.0` resolves to the current latest `0.35.3`.
`agentex-ui/package-lock.json` was regenerated with npm 10 (matching
CI's Node 20 toolchain); the diff is strictly the `sharp` transitive
closure (the `@img/sharp-*` platform binaries, `@img/sharp-libvips-*`,
`@img/colour` replacing `color`, and sharp's own `semver`/`detect-libc`
floor bumps). No `lockfileVersion`/format migration, no file-mode
changes, no application-code changes.

## Transitive-pin safety
`next@15.5.18`'s image optimizer instantiates sharp as `sharp(buffer, {
limitInputPixels, sequentialRead })` — neither option was removed in
0.35.0. The APIs removed in 0.35.0 (`failOnError` constructor prop,
`paletteBitDepth` metadata, `format.jp2k` rename) are **not** used by
next 15.5.18, and the app declares no direct `sharp` usage nor
`next/image` usage. sharp 0.35.0 requires Node ≥ 20.9.0, satisfied by
the `node:20-trixie-slim` build/runtime base.

## Validation
- `npm ci` in `agentex-ui/` — passes (lockfile in sync; CI's exact
install gate)
- `npm run typecheck` (`tsc --noEmit`) — passes
- Diff-scope verified: only `sharp` and its closure changed; `color`
family removed cleanly (was consumed only by sharp)

## Linear
Resolves **GFDVR-20651** — [Trivy] Remediate sharp vulnerabilities
Covers child **GFDVR-20652** — GHSA-f88m-g3jw-g9cj in sharp@0.34.3

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- greptile_comment -->

<h3>Greptile Summary</h3>

Remediates GHSA-f88m-g3jw-g9cj (HIGH) by bumping the transitive `sharp`
dependency from 0.34.3 to 0.35.3, which bundles libvips 8.18.3 and fixes
four libvips CVEs (CVE-2026-33327, -33328, -35590, -35591). The pin is
applied via npm `overrides` in `package.json`, which is the appropriate
mechanism for transitive-only dependencies.

- **`package.json`**: Adds `"sharp": "^0.35.0"` to the existing
`overrides` block alongside the existing `cross-spawn`, `postcss`, and
`tar` overrides.
- **`package-lock.json`**: All `@img/sharp-*` platform binaries move
from 0.34.3 → 0.35.3 and `@img/sharp-libvips-*` from 1.2.0 → 1.3.2;
`color` is cleanly replaced by `@img/colour`; minor floor bumps to
`detect-libc` and `semver`. No application code or `lockfileVersion`
changes.

<details><summary><h3>Confidence Score: 5/5</h3></summary>

Safe to merge — this is a targeted transitive dependency pin with no
application code changes and a well-scoped lockfile diff.

The change is limited to a transitive `sharp` bump via npm `overrides`.
No application code is touched, the lockfile diff is internally
consistent (all `@img/sharp-*` and `@img/sharp-libvips-*` entries move
together), and the removed `color` package is correctly replaced by
`@img/colour` as expected in sharp 0.35.x. The new Node ≥ 20.9.0 engine
constraint is satisfied by the project's existing `node:20` runtime
base.

**Files Needing Attention:** No files require special attention.
</details>

<details><summary><h3>Important Files Changed</h3></summary>

| Filename | Overview |
|----------|----------|
| agentex-ui/package.json | Adds `"sharp": "^0.35.0"` to the existing
npm `overrides` block — the correct mechanism for pinning a transitive
optional dependency without declaring it as a direct dependency. |
| agentex-ui/package-lock.json | Lockfile regenerated to reflect `sharp`
0.34.3 → 0.35.3 and the full transitive closure: `@img/sharp-*` platform
binaries bumped to 0.35.3, `@img/sharp-libvips-*` to 1.3.2, `color`
replaced by `@img/colour`, `detect-libc` 2.0.4 → 2.1.2, `semver` 7.7.2 →
7.8.5, and new platform entries added (riscv64, freebsd-wasm32,
webcontainers-wasm32). Changes are internally consistent and scoped
exclusively to the sharp closure. |

</details>

<sub>Reviews (2): Last reviewed commit: ["Merge branch &#39;main&#39;
into
scale-prodsec/g..."](1464c66)
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Co-authored-by: scale-prodsec[bot] <262621375+scale-prodsec[bot]@users.noreply.github.com>
Co-authored-by: Brandon Allen <brandon.allen@scale.com>

Author: scale-prodsec[bot]