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_axis_escapes.py

@@ -14,11 +14,11 @@ import math
 
 import pytest
 
-from freeroute.board import build_board
-from freeroute.dsn import parse_dsn
-from freeroute.geometry import IntPoint, overlaps_2d, segment_slab
-from freeroute.route.grid_router import GridRouter
-from freeroute.route.pipeline import (
+from rpmroute.board import build_board
+from rpmroute.dsn import parse_dsn
+from rpmroute.geometry import IntPoint, overlaps_2d, segment_slab
+from rpmroute.route.grid_router import GridRouter
+from rpmroute.route.pipeline import (
     _rule_clearance_dsn,
     _rule_width_dsn,
     _via_half_board,
@@ -107,7 +107,7 @@ def test_a_pad_on_the_grid_axes_keeps_the_usual_exits():
 def test_a_slanted_slab_is_tight_where_a_bounding_box_is_not():
     slab = segment_slab(IntPoint(0, 0), IntPoint(10000, 10000), 750)
     # a point beside the diagonal but inside its bounding box
-    from freeroute.geometry import IntBox
+    from rpmroute.geometry import IntBox
 
     assert not overlaps_2d(slab, IntBox(8000, 0, 8100, 100))
     assert overlaps_2d(slab, IntBox(4900, 4900, 5100, 5100))