Add tm_server with SQLite, Svelte UI, and task-master TUI sync.

Introduces the web backend (auth, RBAC, project tokens, revisions),
YouTrack-or-taskmaster backend choice in the TUI, and a first-pass
embedded Svelte UI. The frontend is functional but needs a major rework.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/sqlite/revisions.go

@@ -0,0 +1,120 @@
+package sqlite
+
+import (
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"time"
+)
+
+// Revision is a versioned snapshot of an entity.
+type Revision struct {
+	ID          int64           `json:"id"`
+	EntityType  string          `json:"entityType"`
+	EntityID    string          `json:"entityId"`
+	ProjectID   string          `json:"projectId"`
+	Rev         int             `json:"rev"`
+	At          time.Time       `json:"at"`
+	ActorUserID string          `json:"actorUserId,omitempty"`
+	Op          string          `json:"op"`
+	Snapshot    json.RawMessage `json:"snapshot"`
+}
+
+// AppendRevision stores a new revision snapshot.
+func (db *DB) AppendRevision(entityType, entityID, projectID, op, actorUserID string, snapshot any) (Revision, error) {
+	data, err := json.Marshal(snapshot)
+	if err != nil {
+		return Revision{}, err
+	}
+	var maxRev sql.NullInt64
+	_ = db.SQL.QueryRow(`SELECT MAX(rev) FROM revisions WHERE entity_type = ? AND entity_id = ?`,
+		entityType, entityID).Scan(&maxRev)
+	rev := 1
+	if maxRev.Valid {
+		rev = int(maxRev.Int64) + 1
+	}
+	at := time.Now().UTC()
+	var actor any
+	if actorUserID != "" {
+		actor = actorUserID
+	}
+	res, err := db.SQL.Exec(`
+		INSERT INTO revisions(entity_type, entity_id, project_id, rev, at, actor_user_id, op, snapshot_json)
+		VALUES(?,?,?,?,?,?,?,?)`,
+		entityType, entityID, projectID, rev, formatTime(at), actor, op, string(data))
+	if err != nil {
+		return Revision{}, err
+	}
+	id, _ := res.LastInsertId()
+	return Revision{
+		ID:          id,
+		EntityType:  entityType,
+		EntityID:    entityID,
+		ProjectID:   projectID,
+		Rev:         rev,
+		At:          at,
+		ActorUserID: actorUserID,
+		Op:          op,
+		Snapshot:    data,
+	}, nil
+}
+
+// ListRevisions returns revisions for an entity, newest first.
+func (db *DB) ListRevisions(entityType, entityID string) ([]Revision, error) {
+	rows, err := db.SQL.Query(`
+		SELECT id, entity_type, entity_id, project_id, rev, at, actor_user_id, op, snapshot_json
+		FROM revisions WHERE entity_type = ? AND entity_id = ?
+		ORDER BY rev DESC`, entityType, entityID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	return scanRevisions(rows)
+}
+
+// GetRevision returns one revision by id.
+func (db *DB) GetRevision(id int64) (Revision, error) {
+	row := db.SQL.QueryRow(`
+		SELECT id, entity_type, entity_id, project_id, rev, at, actor_user_id, op, snapshot_json
+		FROM revisions WHERE id = ?`, id)
+	var r Revision
+	var at string
+	var actor sql.NullString
+	var snap string
+	err := row.Scan(&r.ID, &r.EntityType, &r.EntityID, &r.ProjectID, &r.Rev, &at, &actor, &r.Op, &snap)
+	if err == sql.ErrNoRows {
+		return Revision{}, fmt.Errorf("revision %d: not found", id)
+	}
+	if err != nil {
+		return Revision{}, err
+	}
+	r.At = parseTime(at)
+	if actor.Valid {
+		r.ActorUserID = actor.String
+	}
+	r.Snapshot = json.RawMessage(snap)
+	return r, nil
+}
+
+func scanRevisions(rows *sql.Rows) ([]Revision, error) {
+	var out []Revision
+	for rows.Next() {
+		var r Revision
+		var at string
+		var actor sql.NullString
+		var snap string
+		if err := rows.Scan(&r.ID, &r.EntityType, &r.EntityID, &r.ProjectID, &r.Rev, &at, &actor, &r.Op, &snap); err != nil {
+			return nil, err
+		}
+		r.At = parseTime(at)
+		if actor.Valid {
+			r.ActorUserID = actor.String
+		}
+		r.Snapshot = json.RawMessage(snap)
+		out = append(out, r)
+	}
+	if out == nil {
+		out = []Revision{}
+	}
+	return out, rows.Err()
+}