Add configurable topdata wiki visibility policy (#4)

## Summary
- add YAML-backed generated wiki visibility policies for topdata datasets
- centralize page and reference eligibility through a visibility index
- cover eligibility helpers, metadata precedence, derived feat sets, and link suppression with toolkit tests

## Verification
- go test ./...
- module ./validate-topdata.sh with the feature toolkit binary
- module ./build-wiki.sh --force with the feature toolkit binary

Companion module branch: codex-wiki-visibility.

Reviewed-on: https://gitea.westgate.pw/ShadowsOverWestgate/sow-tools/pulls/4
Co-authored-by: vickydotbat <vickydotbat@tutamail.com>
Co-committed-by: vickydotbat <vickydotbat@tutamail.com>

internal/project/project.go

@@ -229,6 +229,7 @@ type TopDataWikiConfig struct {
 	LinkStrategy         string                         `json:"link_strategy" yaml:"link_strategy"`
 	NamespacesFile       string                         `json:"namespaces_file" yaml:"namespaces_file"`
 	TablesFile           string                         `json:"tables_file" yaml:"tables_file"`
+	VisibilityFile       string                         `json:"visibility_file" yaml:"visibility_file"`
 	TemplatesDir         string                         `json:"templates_dir" yaml:"templates_dir"`
 	ManualSectionsDir    string                         `json:"manual_sections_dir" yaml:"manual_sections_dir"`
 	TitlePrefixMinLength int                            `json:"title_prefix_min_length" yaml:"title_prefix_min_length"`
@@ -534,6 +535,7 @@ func (p *Project) ValidateLayout() error {
 		"topdata.wiki.deploy_manifest":          p.Config.TopData.Wiki.DeployManifest,
 		"topdata.wiki.deploy_edit_summary":      p.Config.TopData.Wiki.DeployEditSummary,
 		"topdata.wiki.tables_file":              p.Config.TopData.Wiki.TablesFile,
+		"topdata.wiki.visibility_file":          p.Config.TopData.Wiki.VisibilityFile,
 		"extract.layout":                        p.Config.Extract.Layout,
 		"extract.hak_discovery":                 p.Config.Extract.HAKDiscovery,
 		"autogen.cache.root":                    p.Config.Autogen.Cache.Root,
@@ -567,6 +569,7 @@ func (p *Project) ValidateLayout() error {
 	failures = append(failures, validateTreeRootPath("topdata.wiki.source", effective.TopData.Wiki.Source)...)
 	failures = append(failures, validateRelativePath("topdata.wiki.namespaces_file", effective.TopData.Wiki.NamespacesFile)...)
 	failures = append(failures, validateRelativePath("topdata.wiki.tables_file", effective.TopData.Wiki.TablesFile)...)
+	failures = append(failures, validateRelativePath("topdata.wiki.visibility_file", effective.TopData.Wiki.VisibilityFile)...)
 	failures = append(failures, validateTreeRootPath("topdata.wiki.templates_dir", effective.TopData.Wiki.TemplatesDir)...)
 	failures = append(failures, validateTreeRootPath("topdata.wiki.manual_sections_dir", effective.TopData.Wiki.ManualSectionsDir)...)
 	failures = append(failures, validateRelativePath("autogen.cache.root", effective.Autogen.Cache.Root)...)