test: add smoke test target to Makefile

Add `make smoke` that builds the binary and runs basic commands:
- ctx init (creates .context/)
- ctx status (shows context summary)
- ctx agent (outputs context packet)
- ctx drift (checks for issues)
- ctx add task (adds a task)
- ctx session save (saves session)

This provides a quick verification that the binary works end-to-end,
suitable for CI or pre-release checks.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: josealekhine

.context/TASKS.md

@@ -51,7 +51,7 @@
   - [x] `ctx agent` returns context packet
 - [x] Set unit test coverage target (70% for internal/cli, internal/context)
 - [x] Add coverage reporting to `make test`
-- [ ] Add smoke test to CI/Makefile: build binary, run basic commands
+- [x] Add smoke test to CI/Makefile: build binary, run basic commands
 - [ ] Verify built binary executes subcommands (not silently falling through to root help)
 
 ### Phase 8: Task Archival & Snapshots `#priority:medium` `#area:cli`

Makefile

@@ -2,7 +2,7 @@
 #
 # Common targets for Go developers
 
-.PHONY: build test vet fmt lint clean all release dogfood help test-coverage
+.PHONY: build test vet fmt lint clean all release dogfood help test-coverage smoke
 
 # Default binary name and output
 BINARY := ctx
@@ -47,6 +47,29 @@ test-coverage:
 	echo "Coverage check passed (internal/context >= 70%)"; \
 	rm -f /tmp/ctx-coverage.txt
 
+## smoke: Build and run basic commands to verify binary works
+smoke: build
+	@echo "Running smoke tests..."
+	@TMPDIR=$$(mktemp -d) && \
+	cd $$TMPDIR && \
+	echo "  Testing: ctx --help" && \
+	$(CURDIR)/$(BINARY) --help > /dev/null && \
+	echo "  Testing: ctx init" && \
+	CTX_SKIP_PATH_CHECK=1 $(CURDIR)/$(BINARY) init > /dev/null && \
+	echo "  Testing: ctx status" && \
+	$(CURDIR)/$(BINARY) status > /dev/null && \
+	echo "  Testing: ctx agent" && \
+	$(CURDIR)/$(BINARY) agent > /dev/null && \
+	echo "  Testing: ctx drift" && \
+	$(CURDIR)/$(BINARY) drift > /dev/null && \
+	echo "  Testing: ctx add task 'smoke test task'" && \
+	$(CURDIR)/$(BINARY) add task "smoke test task" > /dev/null && \
+	echo "  Testing: ctx session save" && \
+	$(CURDIR)/$(BINARY) session save > /dev/null && \
+	rm -rf $$TMPDIR && \
+	echo "" && \
+	echo "Smoke tests passed!"
+
 ## vet: Run go vet
 vet:
 	go vet ./...