feat: add MCP endpoint exposing calendar tools over Streamable HTTP

Adds a POST /mcp endpoint (github.com/modelcontextprotocol/go-sdk) with
three tools mirroring the existing /calendar logic: get_calendar_today,
get_calendar_for_date and get_holidays. Bumps go.mod to Go 1.25 (required
by the SDK) and vendors the new dependencies. Also fixes an unanchored
.gitignore rule ("domogeek") that was silently excluding all untracked
files under cmd/domogeek/.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hu8wwahgecuCGfesTKCfEd

vendor/github.com/yosida95/uritemplate/v3/equals.go

@@ -0,0 +1,53 @@
+// Copyright (C) 2016 Kohei YOSHIDA. All rights reserved.
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of The BSD 3-Clause License
+// that can be found in the LICENSE file.
+
+package uritemplate
+
+type CompareFlags uint8
+
+const (
+	CompareVarname CompareFlags = 1 << iota
+)
+
+// Equals reports whether or not two URI Templates t1 and t2 are equivalent.
+func Equals(t1 *Template, t2 *Template, flags CompareFlags) bool {
+	if len(t1.exprs) != len(t2.exprs) {
+		return false
+	}
+	for i := 0; i < len(t1.exprs); i++ {
+		switch t1 := t1.exprs[i].(type) {
+		case literals:
+			t2, ok := t2.exprs[i].(literals)
+			if !ok {
+				return false
+			}
+			if t1 != t2 {
+				return false
+			}
+		case *expression:
+			t2, ok := t2.exprs[i].(*expression)
+			if !ok {
+				return false
+			}
+			if t1.op != t2.op || len(t1.vars) != len(t2.vars) {
+				return false
+			}
+			for n := 0; n < len(t1.vars); n++ {
+				v1 := t1.vars[n]
+				v2 := t2.vars[n]
+				if flags&CompareVarname == CompareVarname && v1.name != v2.name {
+					return false
+				}
+				if v1.maxlen != v2.maxlen || v1.explode != v2.explode {
+					return false
+				}
+			}
+		default:
+			panic("unhandled case")
+		}
+	}
+	return true
+}