Add create-plugin command and improve asset management

- Add new create-plugin command to generate plugins from starter template
- Add manifest name subcommand for template context
- Replace hardcoded asset paths with explicit file patterns in embed directive
- Refactor asset build system to use _setup.mk instead of setup.mk
- Update versioning to use pluginctl manifest id for APP_NAME
- Clean up Makefile by removing redundant bundle name definition

🤖 Generated with [Claude Code](https://claude.ai/code)

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

assets/build/_setup.mk

@@ -42,3 +42,5 @@ ifeq ($(NPM),)
     $(error "npm is not available: see https://www.npmjs.com/get-npm")
 endif
 endif
+
+BUNDLE_NAME ?= $(PLUGIN_ID)-$(PLUGIN_VERSION).tar.gz

assets/build/versioning.mk

@@ -4,7 +4,7 @@
 
 # Used for semver bumping
 PROTECTED_BRANCH := master
-APP_NAME    := $(shell basename -s .git `git config --get remote.origin.url`)
+APP_NAME    := $(shell pluginctl manifest id)
 CURRENT_VERSION := $(shell git describe --abbrev=0 --tags)
 VERSION_PARTS := $(subst ., ,$(subst v,,$(subst -rc, ,$(CURRENT_VERSION))))
 MAJOR := $(word 1,$(VERSION_PARTS))
@@ -108,4 +108,4 @@ major-rc: ## to bump major release candidate version (semver)
 	@echo Bumping $(APP_NAME) to Major RC version $(MAJOR).$(MINOR).$(PATCH)-rc$(RC)
 	git tag -s -a v$(MAJOR).$(MINOR).$(PATCH)-rc$(RC) -m "Bumping $(APP_NAME) to Major RC version $(MAJOR).$(MINOR).$(PATCH)-rc$(RC)"
 	git push origin v$(MAJOR).$(MINOR).$(PATCH)-rc$(RC)
-	@echo Bumped $(APP_NAME) to Major RC version $(MAJOR).$(MINOR).$(PATCH)-rc$(RC)
+	@echo Bumped $(APP_NAME) to Major RC version $(MAJOR).$(MINOR).$(PATCH)-rc$(RC)