feat(api): add public status endpoints with version injection

Replace health_handler with status_handler providing public /status and
/about endpoints. Add build-time version injection via ldflags in
Makefile, and support --version/-v CLI flag.

- Add /status endpoint returning runtime status, uptime, and version
- Add /about endpoint with system metadata (name, description, repo)
- Configure VERSION variable with git describe fallback
- Update swagger docs and api.md for new public endpoints
- Remove deprecated /api/status/test endpoint

Makefile

@@ -1,5 +1,9 @@
 .PHONY: all build swagger test clean dev
 
+# Version injection - can be overridden via make build VERSION=v1.0.0
+VERSION ?= $(shell git describe --tags --always 2>/dev/null || echo "v0.1.0-dev")
+LDFLAGS := -X github.com/ez-api/ez-api/internal/api.Version=$(VERSION)
+
 # Default target
 all: swagger build
 
@@ -10,12 +14,12 @@ swagger:
 
 # Build the binary
 build: swagger
-	@echo "Building ez-api..."
-	go build -o ez-api ./cmd/server
+	@echo "Building ez-api $(VERSION)..."
+	go build -ldflags "$(LDFLAGS)" -o ez-api ./cmd/server
 
 # Build without swagger regeneration (for quick iteration)
 build-fast:
-	go build -o ez-api ./cmd/server
+	go build -ldflags "$(LDFLAGS)" -o ez-api ./cmd/server
 
 # Run tests
 test:
@@ -28,7 +32,7 @@ clean:
 
 # Run in development mode
 dev: swagger
-	go run ./cmd/server
+	go run -ldflags "$(LDFLAGS)" ./cmd/server
 
 # Format code
 fmt: