Add tm_server with SQLite, Svelte UI, and task-master TUI sync.

Introduces the web backend (auth, RBAC, project tokens, revisions),
YouTrack-or-taskmaster backend choice in the TUI, and a first-pass
embedded Svelte UI. The frontend is functional but needs a major rework.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/webembed/embed.go

@@ -0,0 +1,18 @@
+package webembed
+
+import (
+	"embed"
+	"io/fs"
+)
+
+//go:embed all:dist
+var dist embed.FS
+
+// FS returns the embedded static frontend filesystem (contents of dist/).
+func FS() fs.FS {
+	sub, err := fs.Sub(dist, "dist")
+	if err != nil {
+		return dist
+	}
+	return sub
+}