Initial commit

CalDAV and CardDAV checkers sharing a single Go module. Discovery follows
RFC 6764 (/.well-known + SRV/TXT), authenticated probes cover principal,
home-set, collections and a minimal REPORT query on top of go-webdav.
Common shape in internal/dav/; CalDAV adds a scheduling rule.

Surfaces its context URL (and each secure-SRV target) as TLS endpoints via
the EndpointDiscoverer interface, so the dedicated TLS checker can pick
them up without re-parsing observations.

HTML report foregrounds common misconfigs (well-known returning 200,
missing SRV, plaintext-only SRV, missing DAV capability, skipped auth
phase) as action-item callouts before the full phase breakdown.

plugin/caldav/plugin.go

@@ -0,0 +1,16 @@
+// Command plugin is the happyDomain Go-plugin entrypoint for the CalDAV
+// checker. Built with `go build -buildmode=plugin` and loaded at runtime by
+// happyDomain.
+package main
+
+import (
+	"git.happydns.org/checker-dav/caldav"
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+var Version = "custom-build"
+
+func NewCheckerPlugin() (*sdk.CheckerDefinition, sdk.ObservationProvider, error) {
+	caldav.Version = Version
+	return caldav.Definition(), caldav.Provider(), nil
+}

plugin/carddav/plugin.go

@@ -0,0 +1,16 @@
+// Command plugin is the happyDomain Go-plugin entrypoint for the CardDAV
+// checker. Built with `go build -buildmode=plugin` and loaded at runtime by
+// happyDomain.
+package main
+
+import (
+	"git.happydns.org/checker-dav/carddav"
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+var Version = "custom-build"
+
+func NewCheckerPlugin() (*sdk.CheckerDefinition, sdk.ObservationProvider, error) {
+	carddav.Version = Version
+	return carddav.Definition(), carddav.Provider(), nil
+}