Phase 2-6: Git sync, sharing, 2FA, AI integration

- Git: init, commit, log, diff, restore, remotes, push/pull
- Auto-commit on every file save
- Sharing: share/unshare files with other users (ro/rw)
- Shared documents view in sidebar
- 2FA: TOTP setup/verify/disable, enforced at login
- AI: verify spec endpoint (LiteLLM), generate (summarize/prompt/expand)
- Light/dark theme with CSS variables
- File delete (recursive for folders)
- Admin panel + preferences panel
- File creation timestamp display

internal/git/git.go

@@ -0,0 +1,176 @@
+package git
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+// InitRepo initializes a git repo in the user's file directory if not already initialized.
+func InitRepo(dataDir, userID string) error {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	gitDir := filepath.Join(repoDir, ".git")
+	if _, err := os.Stat(gitDir); err == nil {
+		return nil // already initialized
+	}
+	return run(repoDir, "git", "init")
+}
+
+// Commit stages all changes and commits with the given message.
+func Commit(dataDir, userID, message string) error {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	if err := run(repoDir, "git", "add", "-A"); err != nil {
+		return err
+	}
+	// Check if there's anything to commit
+	out, err := output(repoDir, "git", "status", "--porcelain")
+	if err != nil || strings.TrimSpace(out) == "" {
+		return nil // nothing to commit
+	}
+	return runEnv(repoDir, []string{
+		"GIT_AUTHOR_NAME=MarkdownHub",
+		"GIT_AUTHOR_EMAIL=user@markdownhub",
+		"GIT_COMMITTER_NAME=MarkdownHub",
+		"GIT_COMMITTER_EMAIL=user@markdownhub",
+	}, "git", "commit", "-m", message)
+}
+
+// AutoCommit commits with an auto-generated message including timestamp.
+func AutoCommit(dataDir, userID, filename string) error {
+	msg := fmt.Sprintf("Update %s (%s)", filename, time.Now().Format("2006-01-02 15:04"))
+	return Commit(dataDir, userID, msg)
+}
+
+// Log returns recent commit history for a file.
+func Log(dataDir, userID, relPath string, limit int) ([]CommitInfo, error) {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	args := []string{"log", "--format=%H|%ai|%s", fmt.Sprintf("-n%d", limit)}
+	if relPath != "" {
+		args = append(args, "--", relPath)
+	}
+	out, err := output(repoDir, "git", args...)
+	if err != nil {
+		return nil, err
+	}
+	var commits []CommitInfo
+	for _, line := range strings.Split(strings.TrimSpace(out), "\n") {
+		if line == "" {
+			continue
+		}
+		parts := strings.SplitN(line, "|", 3)
+		if len(parts) == 3 {
+			commits = append(commits, CommitInfo{
+				Hash:    parts[0],
+				Date:    parts[1],
+				Message: parts[2],
+			})
+		}
+	}
+	return commits, nil
+}
+
+// Diff returns the diff for a specific commit.
+func Diff(dataDir, userID, commitHash string) (string, error) {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	return output(repoDir, "git", "show", "--stat", "--patch", commitHash)
+}
+
+// Restore restores a file to a specific commit version.
+func Restore(dataDir, userID, relPath, commitHash string) error {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	return run(repoDir, "git", "checkout", commitHash, "--", relPath)
+}
+
+// AddRemote adds a named remote to the user's repo.
+func AddRemote(dataDir, userID, name, url string) error {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	// Remove if exists, then add
+	run(repoDir, "git", "remote", "remove", name)
+	return run(repoDir, "git", "remote", "add", name, url)
+}
+
+// Push pushes to a named remote.
+func Push(dataDir, userID, remoteName, branch string) error {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	if branch == "" {
+		branch = "master"
+	}
+	return run(repoDir, "git", "push", remoteName, branch)
+}
+
+// Pull pulls from a named remote.
+func Pull(dataDir, userID, remoteName, branch string) error {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	if branch == "" {
+		branch = "master"
+	}
+	return run(repoDir, "git", "pull", "--rebase", remoteName, branch)
+}
+
+// ListRemotes returns configured remotes.
+func ListRemotes(dataDir, userID string) ([]RemoteInfo, error) {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	out, err := output(repoDir, "git", "remote", "-v")
+	if err != nil {
+		return nil, err
+	}
+	seen := map[string]bool{}
+	var remotes []RemoteInfo
+	for _, line := range strings.Split(out, "\n") {
+		parts := strings.Fields(line)
+		if len(parts) >= 2 && !seen[parts[0]] {
+			seen[parts[0]] = true
+			remotes = append(remotes, RemoteInfo{Name: parts[0], URL: parts[1]})
+		}
+	}
+	return remotes, nil
+}
+
+// Status returns dirty file count.
+func Status(dataDir, userID string) (int, error) {
+	repoDir := filepath.Join(dataDir, "files", userID)
+	out, err := output(repoDir, "git", "status", "--porcelain")
+	if err != nil {
+		return 0, err
+	}
+	if strings.TrimSpace(out) == "" {
+		return 0, nil
+	}
+	return len(strings.Split(strings.TrimSpace(out), "\n")), nil
+}
+
+type CommitInfo struct {
+	Hash    string `json:"hash"`
+	Date    string `json:"date"`
+	Message string `json:"message"`
+}
+
+type RemoteInfo struct {
+	Name string `json:"name"`
+	URL  string `json:"url"`
+}
+
+func run(dir string, name string, args ...string) error {
+	cmd := exec.Command(name, args...)
+	cmd.Dir = dir
+	cmd.Stdout = nil
+	cmd.Stderr = nil
+	return cmd.Run()
+}
+
+func runEnv(dir string, env []string, name string, args ...string) error {
+	cmd := exec.Command(name, args...)
+	cmd.Dir = dir
+	cmd.Env = append(os.Environ(), env...)
+	return cmd.Run()
+}
+
+func output(dir string, name string, args ...string) (string, error) {
+	cmd := exec.Command(name, args...)
+	cmd.Dir = dir
+	out, err := cmd.Output()
+	return string(out), err
+}