build(deps): bump golang.org/x/net from v0.52.0 to v0.53.0 (#1269)

## Summary

Bumps `golang.org/x/net` from `v0.52.0` to `v0.53.0` to address
`GO-2026-4918` (HTTP/2 transport infinite loop on bad
`SETTINGS_MAX_FRAME_SIZE`). `go mod tidy` also pulls
`golang.org/x/crypto` to v0.50.0 and `golang.org/x/text` to v0.36.0.

## Why now

`govulncheck` is failing on `main` and every open Dependabot PR (#1263,
#1264, #1265) after the 2026-05 Go security release. The findings split
into:

- **One we control** — `golang.org/x/net@v0.52.0` → fixed in `v0.53.0`.
Addressed here.
- **Six stdlib findings** (`GO-2026-4986`, `4982`, `4980`, `4977`,
`4971`, and the stdlib half of `4918`) — all fixed in `go1.26.3`. We
deliberately do **not** pin a Go patch in the workflow: `go-version:
'stable'` will pick up `1.26.3` automatically once the
`actions/go-versions` manifest catches up, with no workflow maintenance.

## Test plan

- [x] `go build ./...`
- [x] `go vet ./...`
- [x] `GOTOOLCHAIN=go1.26.3 govulncheck ./...` → "No vulnerabilities
found."

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

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

go.mod

@@ -73,12 +73,12 @@ require (
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0 // indirect
 	go.opentelemetry.io/otel/trace v1.43.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.4 // indirect
-	golang.org/x/crypto v0.49.0 // indirect
-	golang.org/x/net v0.52.0 // indirect
+	golang.org/x/crypto v0.50.0 // indirect
+	golang.org/x/net v0.53.0 // indirect
 	golang.org/x/oauth2 v0.36.0 // indirect
 	golang.org/x/sync v0.20.0 // indirect
 	golang.org/x/sys v0.43.0 // indirect
-	golang.org/x/text v0.35.0 // indirect
+	golang.org/x/text v0.36.0 // indirect
 	golang.org/x/time v0.15.0 // indirect
 	google.golang.org/api v0.274.0 // indirect
 	google.golang.org/genproto v0.0.0-20260319201613-d00831a3d3e7 // indirect