Multiplayer UI Enhancements

Batch 2 port from citymania-org/cmclient, implemented as console commands (not relying on cmclient's hotkey/toolbar infrastructure, stable and scriptable).

Location Bookmarks (Viewport Locations)

Save/restore the main viewport position and zoom (9 slots), useful for quickly navigating between your factories, stations, and opponent areas during multiplayer.

savelocation <1-9>    # Save current viewport position + zoom
gotolocation <1-9>    # Jump to a saved location

Company Cargo Details

A statistics window listing delivered cargo volume + income per company, togglable between Total / Last Month periods.

company_cargo <company_id>    # Open cargo details window

• The window lists volume and income for each standard cargo, plus a bottom total (identical to cmclient)
• Click the "Cargo" header to toggle between Total and Last Month
• Per-cargo income tracked via CompanyEconomyEntry::cargo_income (XSLFI_COMPANY_CARGO_INCOME save extension), lossless through save/load

Spectate Helper (Watch)

Spectators can quickly locate a company's construction area (jumps to the coordinates of that company's last build action).

watch <company_id>    # Jump viewport to the company's location

Skipped Items and Rationale

cmclient Feature	jrpm Handling
Player list overlay (cm_client_list_gui)	jgrpp already has Online Players window (NetworkClientList), no need to reimplement
Ground detail tooltips (cm_tooltips)	jrpm's LandInfoWindow already covers house/industry/station detail display

Involved Files

• src/jrpm_locations.cpp/.h (new: location bookmarks + company_cargo + watch console commands)
• src/jrpm_cargo_table.cpp/.h (new: cargo details window)
• src/window_type.h (new WindowClass::CompanyCargos)
• src/console_cmds.cpp (command registration)
• src/lang/english.txt (STR_JRPM_CARGOS_* strings)