🛠️ Refactor suggestion

Declare a default all target and mark all entry points as .PHONY.

Most build tools (incl. checkmake) expect a conventional all target to act as the default entry-point and to be listed in the .PHONY declaration together with every recipe that does not create a file of the same name.
Recommend:

+.PHONY: all build install clean test
+
+all: build
+
 build:
 	@echo Building...
 
 install:
-	echo Installing...
+	@echo Installing...

Adds:
• default all alias → CI/CD friendly
• .PHONY list covers every virtual target
• quiets static-analysis "minphony" warnings
• consistent silent-echo for install

In the Makefile at lines 1 to 5, add a default target named "all" that depends
on the "build" target to serve as the conventional entry point. Also, declare
all targets including "all", "build", and "install" as .PHONY to indicate they
are not files. Additionally, modify the "install" target to use silent echo
(prefix with @) for consistency and to reduce noise during execution.