rename project to MultiforaDB

Prose and benchmark tables use MultiforaDB; the binary, the CLI usage
line, the log-message prefix and the default database file use
multiforadb.

Two consequences worth noting:

- build.zig.zon's fingerprint is derived from the package name, so it
  had to change with it (Zig refuses to build otherwise). A consumer
  pinning this package by fingerprint needs updating.
- the default --db path is now multiforadb.log, and getCmdLineOpts
  reports it as dbpath. An existing mongo-lite.log has to be passed
  explicitly with --db.

The e2e harness abbreviated the old name as ML_; that is now MFDB_,
including the documented ML_BIN override (MFDB_BIN) and the scratch
file names. MD_ (mongod) is untouched.

compare-run.sh spawned the server by absolute path under a
sandbox/mongo-lite directory that no longer exists; that block already
runs from tests/e2e, so it uses a relative path now.

The archived reports under tests/e2e/results/ keep the old name: they
record what the old binary measured.

src/commands.zig

@@ -170,7 +170,7 @@ pub fn dispatch(ctx: *Context, msg: *wire.Message, reply: *wire.Reply) !void {
         // rather than turning an applied write into an error the client retries.
         if (ctx.engine.take_compact()) {
             ctx.engine.compact() catch |err| {
-                std.debug.print("mongo-lite: compaction failed: {s}\n", .{@errorName(err)});
+                std.debug.print("multiforadb: compaction failed: {s}\n", .{@errorName(err)});
                 ctx.engine.request_compact();
             };
         }
@@ -226,7 +226,7 @@ fn cmd_ping(_: *Context, _: *wire.Message, reply: *wire.Reply) !void {
 
 fn cmd_build_info(_: *Context, _: *wire.Message, reply: *wire.Reply) !void {
     try reply.put("version", .{ .string = "4.4.0" });
-    try reply.put("gitVersion", .{ .string = "mongo-lite" });
+    try reply.put("gitVersion", .{ .string = "multiforadb" });
     try reply.put("versionArray", .{ .array = try int_array(reply, &.{ 4, 4, 0, 0 }) });
     try reply.put("openssl", .{ .doc = &.{} });
     try reply.put("loaderFlags", .{ .string = "" });
@@ -283,7 +283,7 @@ fn cmd_host_info(ctx: *Context, _: *wire.Message, reply: *wire.Reply) !void {
 
 fn cmd_get_cmd_line_opts(_: *Context, _: *wire.Message, reply: *wire.Reply) !void {
     const argv = try reply.arena_alloc().alloc(bson.Pair, 2);
-    argv[0] = .{ .key = "dbpath", .value = .{ .string = "mongo-lite.log" } };
+    argv[0] = .{ .key = "dbpath", .value = .{ .string = "multiforadb.log" } };
     argv[1] = .{ .key = "port", .value = .{ .int32 = 27017 } };
     try reply.put("argv", .{ .array = &.{} });
     try reply.put("parsed", .{ .doc = argv });