orders: add position management commands and overlay

[Robuske]

Summary

Adds direct manager-order position management to orders:

• orders positions [--show-id] lists fort-wide manager orders in displayed priority order.
• orders move <current-position> <new-position> [--show-id] moves the existing order pointer within world.manager_orders.all.
• orders.position adds inline position fields to the Work Orders screen and uses the same move logic as the command.
• Shares Work Orders list geometry between the existing search overlay and the new position overlay.
  • The existing search result indicator was moved a bit to avoid overlap (see second screenshot).
• Adds documentation, a Future changelog entry, and contributor metadata.

The native orders plugin dispatches the new subcommands to Lua. Expected validation failures are returned normally, avoiding the extra Failed Lua call message.

Testing

• Built the orders plugin with the DFHack Visual Studio build.

• Ran:

  test -d C:/Users/rodbu/Developer/Dwarf/dfhack/test -t orders
  

  Result: 18/18 tests passed, 227/227 checks passed.

• Performed in-game testing of command moves, validation errors, inline editing, cancellation, focus handling, scrolling, and search-overlay interaction.

Normal	Editing + Search result indicator

Documentation

Includes orders command and orders.position overlay documentation, plus the required docs/changelog.txt entry.