Scaffold GitManager multi-repo dashboard

Runnable skeleton per AGENT.md: Echo server (/, /help, /healthz, /api/repos), read-only repo scanner with in-memory index, the internal/git boundary, the <repo-list> web component with design tokens, and dev tooling (Dockerfile, docker-compose, air, .env.example).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

go.mod

@@ -0,0 +1,21 @@
+module gitmanager
+
+go 1.26
+
+require (
+	github.com/joho/godotenv v1.5.1
+	github.com/labstack/echo/v4 v4.15.4
+)
+
+require (
+	github.com/labstack/gommon v0.5.0 // indirect
+	github.com/mattn/go-colorable v0.1.15 // indirect
+	github.com/mattn/go-isatty v0.0.22 // indirect
+	github.com/valyala/bytebufferpool v1.0.0 // indirect
+	github.com/valyala/fasttemplate v1.2.2 // indirect
+	golang.org/x/crypto v0.53.0 // indirect
+	golang.org/x/net v0.56.0 // indirect
+	golang.org/x/sys v0.46.0 // indirect
+	golang.org/x/text v0.38.0 // indirect
+	golang.org/x/time v0.15.0 // indirect
+)