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/cache/cache_test.go

@@ -0,0 +1,165 @@
+package cache
+
+import (
+	"testing"
+	"time"
+
+	"git.wntrmute.dev/mc/mcdoc/internal/render"
+)
+
+func TestSetAndGetRepo(t *testing.T) {
+	c := New()
+
+	info := &RepoInfo{
+		Name:        "testrepo",
+		Description: "A test repo",
+		CommitSHA:   "abc123",
+		FetchedAt:   time.Now(),
+		Docs: []*Document{
+			{Repo: "testrepo", URLPath: "README", Title: "README", HTML: "<p>hello</p>"},
+			{Repo: "testrepo", URLPath: "ARCHITECTURE", Title: "Architecture", HTML: "<p>arch</p>"},
+		},
+	}
+	c.SetRepo(info)
+
+	got, ok := c.GetRepo("testrepo")
+	if !ok {
+		t.Fatal("expected repo to exist")
+	}
+	if got.Name != "testrepo" {
+		t.Fatalf("got name %q, want %q", got.Name, "testrepo")
+	}
+	if len(got.Docs) != 2 {
+		t.Fatalf("got %d docs, want 2", len(got.Docs))
+	}
+}
+
+func TestGetDocument(t *testing.T) {
+	c := New()
+	c.SetRepo(&RepoInfo{
+		Name: "r",
+		Docs: []*Document{
+			{Repo: "r", URLPath: "foo/bar", Title: "Bar", HTML: "<p>bar</p>"},
+		},
+	})
+
+	doc, ok := c.GetDocument("r", "foo/bar")
+	if !ok {
+		t.Fatal("expected document to exist")
+	}
+	if doc.Title != "Bar" {
+		t.Fatalf("got title %q, want %q", doc.Title, "Bar")
+	}
+
+	_, ok = c.GetDocument("r", "nonexistent")
+	if ok {
+		t.Fatal("expected document to not exist")
+	}
+
+	_, ok = c.GetDocument("nonexistent", "foo/bar")
+	if ok {
+		t.Fatal("expected repo to not exist")
+	}
+}
+
+func TestListReposSorted(t *testing.T) {
+	c := New()
+	c.SetRepo(&RepoInfo{Name: "mcr"})
+	c.SetRepo(&RepoInfo{Name: "abc"})
+	c.SetRepo(&RepoInfo{Name: "mcp"})
+
+	repos := c.ListRepos()
+	if len(repos) != 3 {
+		t.Fatalf("got %d repos, want 3", len(repos))
+	}
+	if repos[0].Name != "abc" || repos[1].Name != "mcp" || repos[2].Name != "mcr" {
+		t.Fatalf("unexpected order: %s, %s, %s", repos[0].Name, repos[1].Name, repos[2].Name)
+	}
+}
+
+func TestDocSortOrder(t *testing.T) {
+	c := New()
+	c.SetRepo(&RepoInfo{
+		Name: "r",
+		Docs: []*Document{
+			{URLPath: "CLAUDE"},
+			{URLPath: "zebra"},
+			{URLPath: "README"},
+			{URLPath: "ARCHITECTURE"},
+			{URLPath: "alpha"},
+			{URLPath: "RUNBOOK"},
+		},
+	})
+
+	repo, _ := c.GetRepo("r")
+	expected := []string{"README", "ARCHITECTURE", "RUNBOOK", "CLAUDE", "alpha", "zebra"}
+	for i, doc := range repo.Docs {
+		if doc.URLPath != expected[i] {
+			t.Errorf("position %d: got %q, want %q", i, doc.URLPath, expected[i])
+		}
+	}
+}
+
+func TestReadyState(t *testing.T) {
+	c := New()
+	if c.IsReady() {
+		t.Fatal("new cache should not be ready")
+	}
+	c.SetReady()
+	if !c.IsReady() {
+		t.Fatal("cache should be ready after SetReady")
+	}
+}
+
+func TestGetCommitSHA(t *testing.T) {
+	c := New()
+	if sha := c.GetCommitSHA("nope"); sha != "" {
+		t.Fatalf("expected empty sha, got %q", sha)
+	}
+
+	c.SetRepo(&RepoInfo{Name: "r", CommitSHA: "abc123"})
+	if sha := c.GetCommitSHA("r"); sha != "abc123" {
+		t.Fatalf("expected abc123, got %q", sha)
+	}
+}
+
+func TestAtomicRepoSwap(t *testing.T) {
+	c := New()
+	c.SetRepo(&RepoInfo{
+		Name: "r",
+		Docs: []*Document{{URLPath: "old", Title: "Old"}},
+	})
+
+	c.SetRepo(&RepoInfo{
+		Name: "r",
+		Docs: []*Document{{URLPath: "new", Title: "New"}},
+	})
+
+	repo, _ := c.GetRepo("r")
+	if len(repo.Docs) != 1 || repo.Docs[0].URLPath != "new" {
+		t.Fatal("expected atomic swap to replace docs")
+	}
+}
+
+func TestRemoveRepo(t *testing.T) {
+	c := New()
+	c.SetRepo(&RepoInfo{Name: "r"})
+	c.RemoveRepo("r")
+
+	_, ok := c.GetRepo("r")
+	if ok {
+		t.Fatal("expected repo to be removed")
+	}
+}
+
+// Ensure Document's Headings field works with the render package type.
+func TestDocumentHeadingsType(t *testing.T) {
+	doc := &Document{
+		Headings: []render.Heading{
+			{Level: 1, ID: "title", Text: "Title"},
+		},
+	}
+	if doc.Headings[0].Text != "Title" {
+		t.Fatal("unexpected heading text")
+	}
+}