feat: default list_alerts to active alerts only

Change list_alerts (MCP tool) and alerts (CLI command) to show only
active (non-silenced, non-inhibited) alerts by default. Add state=all
option and --all CLI flag to show all alerts when needed.

- MCP: list_alerts with no state param now returns active alerts only
- MCP: list_alerts with state=all returns all alerts (previous default)
- CLI: alerts command defaults to active, --all shows everything
- Add tests for new default behavior and state=all option
- Update README with new CLI examples
- Bump version to 0.3.0
- Clarify version bumping rules in CLAUDE.md

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

internal/mcp/server.go

@@ -45,7 +45,7 @@ type ServerConfig struct {
 func DefaultNixOSConfig() ServerConfig {
 	return ServerConfig{
 		Name:           "nixos-options",
-		Version:        "0.2.1",
+		Version:        "0.3.0",
 		DefaultChannel: "nixos-stable",
 		SourceName:     "nixpkgs",
 		Mode:           ModeOptions,
@@ -65,7 +65,7 @@ This ensures option documentation matches the nixpkgs version the project actual
 func DefaultNixpkgsPackagesConfig() ServerConfig {
 	return ServerConfig{
 		Name:           "nixpkgs-packages",
-		Version:        "0.2.1",
+		Version:        "0.3.0",
 		DefaultChannel: "nixos-stable",
 		SourceName:     "nixpkgs",
 		Mode:           ModePackages,
@@ -83,7 +83,7 @@ This ensures package information matches the nixpkgs version the project actuall
 func DefaultMonitoringConfig() ServerConfig {
 	return ServerConfig{
 		Name:    "lab-monitoring",
-		Version: "0.2.0",
+		Version: "0.3.0",
 		Mode:    ModeCustom,
 		Instructions: `Lab Monitoring MCP Server - Query Prometheus metrics and Alertmanager alerts.
 
@@ -102,7 +102,7 @@ All queries are executed against live Prometheus, Alertmanager, and Loki HTTP AP
 func DefaultHomeManagerConfig() ServerConfig {
 	return ServerConfig{
 		Name:           "hm-options",
-		Version:        "0.2.1",
+		Version:        "0.3.0",
 		DefaultChannel: "hm-stable",
 		SourceName:     "home-manager",
 		Mode:           ModeOptions,