refactor(repo): consolidate openflare-server to root and move subprojects to internal/apps

- Merge all files inside openflare-server to the repository root directory.
- Relocate agent, relay, and flared subprojects from internal/ to internal/apps/.
- Combine docker-compose files and update build context paths to root.
- Update GitHub workflows and Dockerfiles to refer to new directories and package names.
- Rewrite Go package imports across all files.
- Resolve database renew test race condition and clean up docs.

pkg/push/template_test.go

@@ -0,0 +1,75 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package push
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestParseTemplate(t *testing.T) {
+	tests := []struct {
+		name     string
+		template string
+		body     map[string]any
+		expected string
+	}{
+		{
+			name:     "simple replacement",
+			template: "hello {{name}}",
+			body:     map[string]any{"name": "world"},
+			expected: "hello world",
+		},
+		{
+			name:     "multiple replacements",
+			template: "{{greeting}} {{name}}!",
+			body:     map[string]any{"greeting": "Hello", "name": "Alice"},
+			expected: "Hello Alice!",
+		},
+		{
+			name:     "missing key preserves placeholder",
+			template: "hello {{name}} and {{other}}",
+			body:     map[string]any{"name": "world"},
+			expected: "hello world and {{other}}",
+		},
+		{
+			name:     "unbalanced placeholders",
+			template: "hello {{name",
+			body:     map[string]any{"name": "world"},
+			expected: "hello {{name",
+		},
+		{
+			name:     "nil value",
+			template: "val: {{val}}",
+			body:     map[string]any{"val": nil},
+			expected: "val: ",
+		},
+		{
+			name:     "basic types",
+			template: "int: {{i}}, float: {{f}}, bool: {{b}}",
+			body:     map[string]any{"i": 123, "f": 45.67, "b": true},
+			expected: "int: 123, float: 45.67, bool: true",
+		},
+		{
+			name:     "complex type slice",
+			template: "items: {{items}}",
+			body:     map[string]any{"items": []string{"a", "b"}},
+			expected: `items: ["a","b"]`,
+		},
+		{
+			name:     "complex type map",
+			template: "obj: {{obj}}",
+			body:     map[string]any{"obj": map[string]any{"key": "value"}},
+			expected: `obj: {"key":"value"}`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := ParseTemplate(tt.template, tt.body)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}