Rename to rpmroute

The router began as a port of FreeRouting and has grown its own engine
(negotiated congestion, tree nets, exact checks, axis escapes), and
'freeroute' was one letter from the project it no longer follows. The
package, module and command are now rpmroute; the freeroute command stays
as an alias, and the RPMROUTE / RPMROUTE_ORACLE_JAVA variables fall back
to the old FREEROUTE names. Version 2026.10.07. Routing is unchanged: a
PCBench board routes to a byte-identical session either way.

tests/route/test_window_reroute.py

@@ -3,11 +3,11 @@ it leaves fewer connections unrouted."""
 
 from __future__ import annotations
 
-from freeroute.board import build_board
-from freeroute.dsn import parse_dsn
-from freeroute.geometry import IntBox
-from freeroute.route.grid_router import GridRouter
-from freeroute.route.pipeline import _rule_clearance_dsn, _rule_width_dsn, route_dsn_board_exact
+from rpmroute.board import build_board
+from rpmroute.dsn import parse_dsn
+from rpmroute.geometry import IntBox
+from rpmroute.route.grid_router import GridRouter
+from rpmroute.route.pipeline import _rule_clearance_dsn, _rule_width_dsn, route_dsn_board_exact
 
 
 def _slot(gap: int = 640, far: bool = False) -> str:
@@ -101,7 +101,7 @@ def test_a_spent_budget_starts_no_window():
 
 
 def test_window_board_keeps_far_items_of_the_rerouted_nets_only():
-    from freeroute.route.window import _item_box, _window_board
+    from rpmroute.route.window import _item_box, _window_board
 
     board = build_board(parse_dsn(_slot(far=True)))
     items = [(item, _item_box(item)) for item in board.get_items()]
@@ -115,7 +115,7 @@ def test_window_board_keeps_far_items_of_the_rerouted_nets_only():
 def test_a_connection_ending_outside_the_window_gets_no_copper():
     """Its far end has no grid cells; a stub out to it would cross items the
     window board never saw."""
-    from freeroute.route.exact_router import route_board_exact
+    from rpmroute.route.exact_router import route_board_exact
 
     dsn = parse_dsn(_slot(far=True))
     s = dsn.resolution.value