Rewrite the logger in Rust; add install targets

vitals-log replaces the bash sampler and writes the same CSV layout.
The crate is now a library plus two binaries. dist/ holds the systemd
unit and desktop entry templates, installed by make install.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Makefile

@@ -0,0 +1,42 @@
+# Per-user install: binaries, the systemd timer that runs the logger, and the
+# desktop entry for the viewer.
+
+PREFIX  ?= $(HOME)/.local
+BINDIR  := $(PREFIX)/bin
+APPDIR  := $(or $(XDG_DATA_HOME),$(HOME)/.local/share)/applications
+UNITDIR := $(or $(XDG_CONFIG_HOME),$(HOME)/.config)/systemd/user
+
+.PHONY: build test install install-bin install-units install-desktop uninstall
+
+build:
+	cargo build --release
+
+test:
+	cargo test
+
+install: install-bin install-units install-desktop
+
+install-bin: build
+	install -Dm755 target/release/vitals $(BINDIR)/vitals
+	install -Dm755 target/release/vitals-log $(BINDIR)/vitals-log
+
+# dist/ files carry an @BINDIR@ placeholder so they point at wherever PREFIX put the binaries.
+install-units:
+	install -d $(UNITDIR)
+	sed 's|@BINDIR@|$(BINDIR)|' dist/vitals-log.service > $(UNITDIR)/vitals-log.service
+	install -m644 dist/vitals-log.timer $(UNITDIR)/vitals-log.timer
+	systemctl --user daemon-reload
+	systemctl --user enable --now vitals-log.timer
+
+install-desktop:
+	install -d $(APPDIR)
+	sed 's|@BINDIR@|$(BINDIR)|' dist/vitals.desktop > $(APPDIR)/vitals.desktop
+	-update-desktop-database $(APPDIR)
+
+# Leaves the logs in ~/.local/state/vitals alone.
+uninstall:
+	-systemctl --user disable --now vitals-log.timer
+	rm -f $(UNITDIR)/vitals-log.service $(UNITDIR)/vitals-log.timer
+	rm -f $(APPDIR)/vitals.desktop $(BINDIR)/vitals $(BINDIR)/vitals-log
+	-systemctl --user daemon-reload
+	-update-desktop-database $(APPDIR)