### Description
Replaces all remaining direct `gopkg.in/yaml.v3` imports with
`go.yaml.in/yaml/v4` across models, modules, routers, services, and
integration tests. `gopkg.in/yaml.v3` moves from a direct to an indirect
dependency in `go.mod`.
#### API compatibility
The yaml.Node type, node.Kind/node.Content traversal style
(modules/markup/markdown/convertyaml.go), and the
UnmarshalYAML(*yaml.Node) interface signature
(modules/optional/serialization.go) are all preserved in v4 — no
call-site changes were required beyond the import path.
**Related:**
- https://github.com/go-gitea/gitea/pull/36564#issuecomment-4526536805
---------
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 4.8) <noreply@anthropic.com>
## Overview
This PR updates the Go toolchain version from `1.25.5` to `1.25.6` for
the Gitea project.
## Changes
### Toolchain Update
- **Go Toolchain**: Updated from `go1.25.5` to `go1.25.6`
This is a minor toolchain version bump that ensures the project uses the
latest patch release of Go 1.25.
## Security Improvements
While this PR primarily addresses the toolchain update, the project
maintains a strong security posture through:
### Current Security Measures
```log
Vulnerability #1: GO-2026-4342
Excessive CPU consumption when building archive index in archive/zip
More info: https://pkg.go.dev/vuln/GO-2026-4342
Standard library
Found in: archive/zip@go1.25.5
Fixed in: archive/zip@go1.25.6
Example traces found:
#1: modules/packages/nuget/metadata.go:217:25: nuget.ParseNuspecMetaData calls zip.Reader.Open
Vulnerability #2: GO-2026-4341
Memory exhaustion in query parameter parsing in net/url
More info: https://pkg.go.dev/vuln/GO-2026-4341
Standard library
Found in: net/url@go1.25.5
Fixed in: net/url@go1.25.6
Example traces found:
#1: modules/storage/minio.go:284:34: storage.MinioStorage.URL calls url.ParseQuery
#2: routers/api/v1/repo/action.go:1640:29: repo.DownloadArtifactRaw calls url.URL.Query
Vulnerability #3: GO-2026-4340
Handshake messages may be processed at the incorrect encryption level in
crypto/tls
More info: https://pkg.go.dev/vuln/GO-2026-4340
Standard library
Found in: crypto/tls@go1.25.5
Fixed in: crypto/tls@go1.25.6
Example traces found:
#1: services/auth/source/ldap/source_search.go:129:25: ldap.dial calls ldap.Conn.StartTLS, which calls tls.Conn.Handshake
#2: modules/graceful/server.go:156:14: graceful.Server.Serve calls http.Server.Serve, which eventually calls tls.Conn.HandshakeContext
#3: modules/lfs/content_store.go:132:27: lfs.hashingReader.Read calls tls.Conn.Read
#4: modules/proxyprotocol/conn.go:91:21: proxyprotocol.Conn.Write calls tls.Conn.Write
#5: modules/session/virtual.go:168:39: session.VirtualStore.Release calls couchbase.CouchbaseProvider.Exist, which eventually calls tls.Dial
#6: services/auth/source/ldap/source_search.go:120:22: ldap.dial calls ldap.DialTLS, which calls tls.DialWithDialer
#7: services/migrations/gogs.go:114:34: migrations.client calls http.Transport.RoundTrip, which eventually calls tls.Dialer.DialContext
```
## Breaking Changes
None expected. This is a minor toolchain patch update.
