refactor: serve the api specs as plain json (#38715)

The api specs were Go templates whose committed form was not a valid
swagger document, so `swagger-validate`, `generate-openapi.go` and
`.spectral.yaml` each worked around it. They are now plain json,
substituted at serve time.

Renaming them off `.tmpl` also stops `make fmt` rewriting them, which
used to bump their mtime and silently skip the next `make
generate-swagger`.

Also enables stricter spectral linting: extends `lint-swagger` to the
OpenAPI 3 spec, turns on `openapi-tags`, `operation-singular-tag` and
`operation-tag-defined`, adds a top-level `tags` array with descriptions
to the swagger input, and drops the redundant `repository` tag from
`POST /user/repos`.

---------

Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>

build/openapi3gen/convert.go

@@ -23,8 +23,8 @@ import (
 var rxDeprecated = regexp.MustCompile(`(?i)(?:^|[\n.;])\s*deprecated\b`)
 
 // Convert parses a Swagger 2.0 spec and returns an OAS3 spec, applying
-// Gitea-specific post-processing: file-schema fixups, URI formats,
-// deprecated flags, and shared-enum extraction.
+// Gitea-specific post-processing: server URL, file-schema fixups, URI
+// formats, deprecated flags, and shared-enum extraction.
 //
 // astEnumMap is a value-set-key → Go-type-name(s) map (built by
 // ScanSwaggerEnumTypes). When a value set is shared by multiple Go types,
@@ -42,6 +42,7 @@ func Convert(swaggerJSON []byte, astEnumMap map[string][]string) (*openapi3.T, e
 		return nil, fmt.Errorf("converting to openapi 3.0: %w", err)
 	}
 
+	oas3.Servers = openapi3.Servers{{URL: swagger2.BasePath}}
 	fixFileSchemas(oas3)
 	addURIFormats(oas3)
 	addDeprecatedFlags(oas3)