Initial lookbook implementation

Pinterest-style visual bookmarking app with:
- URL metadata extraction (OG/Twitter meta, oEmbed fallback)
- Image caching in Postgres with 480px thumbnails
- Multi-tag filtering with Ctrl/Cmd for OR mode
- Fuzzy tag suggestions and inline tag editing
- Browser console auth() with first-use password setup
- Brutalist UI with Commit Mono font and Pico CSS
- Light/dark mode via browser preference

vendor/github.com/mfridman/interpolate/env.go

@@ -0,0 +1,53 @@
+package interpolate
+
+import (
+	"runtime"
+	"strings"
+)
+
+// Env is an interface for getting environment variables by name and returning a boolean indicating
+// whether the variable was found.
+type Env interface {
+	Get(key string) (string, bool)
+}
+
+// NewSliceEnv creates an Env from a slice of environment variables in the form "key=value".
+//
+// This can be used with [os.Environ] to create an Env.
+func NewSliceEnv(env []string) Env {
+	envMap := mapEnv{}
+	for _, l := range env {
+		parts := strings.SplitN(l, "=", 2)
+		if len(parts) == 2 {
+			envMap[normalizeKeyName(parts[0])] = parts[1]
+		}
+	}
+	return envMap
+}
+
+// NewMapEnv creates an Env from a map of environment variables.
+func NewMapEnv(env map[string]string) Env {
+	envMap := mapEnv{}
+	for k, v := range env {
+		envMap[normalizeKeyName(k)] = v
+	}
+	return envMap
+}
+
+type mapEnv map[string]string
+
+func (m mapEnv) Get(key string) (string, bool) {
+	if m == nil {
+		return "", false
+	}
+	val, ok := m[normalizeKeyName(key)]
+	return val, ok
+}
+
+// Windows isn't case sensitive for env
+func normalizeKeyName(key string) string {
+	if runtime.GOOS == "windows" {
+		return strings.ToUpper(key)
+	}
+	return key
+}