Add a VHS tape that demos the full task-master feature set.

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

Makefile

@@ -4,7 +4,7 @@ VERSION_PKG := task/internal/version
 GIT_HASH    := $(shell git rev-parse --short HEAD 2>/dev/null || echo unknown)
 LDFLAGS     := -X $(VERSION_PKG).BuildVersion=$(GIT_HASH)
 
-.PHONY: build run version
+.PHONY: build run version demo
 
 build:
 	go build -ldflags "$(LDFLAGS)" -o bin/$(BINARY) $(CMD)
@@ -14,3 +14,7 @@ run: build
 
 version: build
 	./bin/$(BINARY) version
+
+# Record a full feature walkthrough (requires vhs: https://github.com/charmbracelet/vhs)
+demo:
+	vhs demo.tape