Implement mcdoc v0.1.0: public documentation server

Single-binary Go server that fetches markdown from Gitea (mc org),
renders to HTML with goldmark (GFM, chroma syntax highlighting,
heading anchors), and serves a navigable read-only documentation site.

Features:
- Boot fetch with retry, webhook refresh, 15-minute poll fallback
- In-memory cache with atomic per-repo swap
- chi router with htmx partial responses for SPA-like navigation
- HMAC-SHA256 webhook validation
- Responsive CSS, TOC generation, priority doc ordering
- $PORT env var support for MCP agent port assignment

33 tests across config, cache, render, and server packages.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/config/config_test.go

@@ -0,0 +1,154 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestLoadValidConfig(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "mcdoc.toml")
+
+	content := `
+[server]
+listen_addr = ":9090"
+
+[gitea]
+url = "https://git.example.com"
+org = "myorg"
+webhook_secret = "secret123"
+poll_interval = "5m"
+fetch_timeout = "10s"
+max_concurrency = 2
+
+[gitea.exclude_paths]
+patterns = ["vendor/"]
+
+[gitea.exclude_repos]
+names = ["ignore-me"]
+
+[log]
+level = "debug"
+`
+	if err := os.WriteFile(path, []byte(content), 0600); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+
+	if cfg.Server.ListenAddr != ":9090" {
+		t.Fatalf("listen_addr = %q, want :9090", cfg.Server.ListenAddr)
+	}
+	if cfg.Gitea.URL != "https://git.example.com" {
+		t.Fatalf("gitea.url = %q", cfg.Gitea.URL)
+	}
+	if cfg.Gitea.Org != "myorg" {
+		t.Fatalf("gitea.org = %q", cfg.Gitea.Org)
+	}
+	if cfg.Gitea.PollInterval.Duration != 5*time.Minute {
+		t.Fatalf("poll_interval = %v", cfg.Gitea.PollInterval.Duration)
+	}
+	if cfg.Gitea.FetchTimeout.Duration != 10*time.Second {
+		t.Fatalf("fetch_timeout = %v", cfg.Gitea.FetchTimeout.Duration)
+	}
+	if cfg.Gitea.MaxConcurrency != 2 {
+		t.Fatalf("max_concurrency = %d", cfg.Gitea.MaxConcurrency)
+	}
+	if len(cfg.Gitea.ExcludePaths.Patterns) != 1 {
+		t.Fatalf("exclude_paths = %v", cfg.Gitea.ExcludePaths.Patterns)
+	}
+	if len(cfg.Gitea.ExcludeRepos.Names) != 1 {
+		t.Fatalf("exclude_repos = %v", cfg.Gitea.ExcludeRepos.Names)
+	}
+	if cfg.Log.Level != "debug" {
+		t.Fatalf("log.level = %q", cfg.Log.Level)
+	}
+}
+
+func TestLoadDefaults(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "mcdoc.toml")
+
+	// Minimal config — everything should get defaults
+	if err := os.WriteFile(path, []byte(""), 0600); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+
+	if cfg.Server.ListenAddr != ":8080" {
+		t.Fatalf("default listen_addr = %q, want :8080", cfg.Server.ListenAddr)
+	}
+	if cfg.Gitea.URL != "https://git.wntrmute.dev" {
+		t.Fatalf("default gitea.url = %q", cfg.Gitea.URL)
+	}
+	if cfg.Gitea.PollInterval.Duration != 15*time.Minute {
+		t.Fatalf("default poll_interval = %v", cfg.Gitea.PollInterval.Duration)
+	}
+}
+
+func TestLoadMissingFile(t *testing.T) {
+	_, err := Load("/nonexistent/mcdoc.toml")
+	if err == nil {
+		t.Fatal("expected error for missing file")
+	}
+}
+
+func TestPortEnvOverride(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "mcdoc.toml")
+	if err := os.WriteFile(path, []byte(""), 0600); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	t.Setenv("PORT", "12345")
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+	if cfg.Server.ListenAddr != ":12345" {
+		t.Fatalf("PORT override: got %q, want :12345", cfg.Server.ListenAddr)
+	}
+}
+
+func TestEnvOverride(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "mcdoc.toml")
+	if err := os.WriteFile(path, []byte(""), 0600); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	t.Setenv("MCDOC_GITEA_ORG", "custom-org")
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+	if cfg.Gitea.Org != "custom-org" {
+		t.Fatalf("env override: got %q, want custom-org", cfg.Gitea.Org)
+	}
+}
+
+func TestValidationFailsOnEmptyURL(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "mcdoc.toml")
+	content := `
+[gitea]
+url = ""
+`
+	if err := os.WriteFile(path, []byte(content), 0600); err != nil {
+		t.Fatalf("write config: %v", err)
+	}
+
+	_, err := Load(path)
+	if err == nil {
+		t.Fatal("expected validation error for empty gitea.url")
+	}
+}