fix(template): parameterize scaffold with __PROJECT_NAME__/__MODULE_PATH__ (gitea-mcp#44)

template-go-web was seeded from the real `hostexecutor` project and never
parameterized: go.mod hardcoded `module gitea.d-ma.be/mathias/hostexecutor` and
`hostexecutor` appeared throughout (cmd dir, Dockerfile, Taskfile, CI, context
docs). create_project_from_template therefore substituted nothing and returned
a "no placeholders" partial_failure on the zero-config default path.

Replaced the full module path with __MODULE_PATH__ and the bare project name
with __PROJECT_NAME__ (incl. renaming cmd/hostexecutor → cmd/__PROJECT_NAME__),
matching the substitution the tool performs. Also drops the stale gitea.d-ma.be
host (the placeholder resolves to git.d-ma.be/<owner>/<name>).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/web/index.templ

@@ -1,8 +1,8 @@
 package web
 
 templ Index() {
-	@Layout("hostexecutor") {
-		<h1 class="text-3xl font-semibold mb-6">hostexecutor</h1>
+	@Layout("__PROJECT_NAME__") {
+		<h1 class="text-3xl font-semibold mb-6">__PROJECT_NAME__</h1>
 		<button hx-get="/api/hello" hx-target="#out"
 			class="px-4 py-2 bg-slate-900 text-white rounded-md hover:bg-slate-700">
 			Say hello