add snonux static microblog generator

Full Go implementation with:
- txt/md/image/audio input processing, URL auto-linking in .txt files
- Paginated HTML output with Atom feed
- 11 visual themes: neon, terminal, synthwave, minimal, brutalist, paper,
  aurora, matrix, ocean, retro, glass (selectable via --theme flag)
- Keyboard navigation (j/k/arrows, Enter modal, h/l page nav)
- Shared nav templates (navhints, navmodal, navscript) across all themes
- Magefile build automation; integration test suite covering all themes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/internal/generator/themes.go b/internal/generator/themes.go
new file mode 100644
index 0000000..8de6193
--- /dev/null
+++ b/internal/generator/themes.go
@@ -0,0 +1,44 @@
+package generator
+
+// themeRegistry maps theme names to their HTML template strings.
+// Each template must use {{template "navhints" .}}, {{template "navmodal" .}},
+// and {{template "navscript" .}} — these are defined in shared.go (navDefs).
+var themeRegistry = map[string]string{
+	"neon":      neonTemplate,
+	"terminal":  terminalTemplate,
+	"synthwave": synthwaveTemplate,
+	"minimal":   minimalTemplate,
+	"brutalist": brutalistTemplate,
+	"paper":     paperTemplate,
+	"aurora":    auroraTemplate,
+	"matrix":    matrixTemplate,
+	"ocean":     oceanTemplate,
+	"retro":     retroTemplate,
+	"glass":     glassTemplate,
+}
+
+// getTheme returns the HTML template string for the given theme name.
+// Falls back to the neon theme if the name is unknown.
+func getTheme(name string) string {
+	if t, ok := themeRegistry[name]; ok {
+		return t
+	}
+	return neonTemplate
+}
+
+// ListThemes returns a sorted list of all available theme names.
+func ListThemes() []string {
+	names := make([]string, 0, len(themeRegistry))
+	for k := range themeRegistry {
+		names = append(names, k)
+	}
+	// Sort for deterministic output in --help text.
+	for i := 0; i < len(names); i++ {
+		for j := i + 1; j < len(names); j++ {
+			if names[i] > names[j] {
+				names[i], names[j] = names[j], names[i]
+			}
+		}
+	}
+	return names
+}