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_grid_exact_agreement.py

@@ -12,11 +12,11 @@ import math
 
 import pytest
 
-from freeroute.board import build_board
-from freeroute.dsn import parse_dsn
-from freeroute.geometry import IntBox, Simplex
-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 IntBox, Simplex
+from rpmroute.route.grid_router import GridRouter
+from rpmroute.route.pipeline import (
     _rule_clearance_dsn,
     _rule_width_dsn,
     _via_half_board,
@@ -268,9 +268,9 @@ def test_a_via_by_a_chamfered_corner_is_judged_round():
     """The grid keeps a via's centre its radius plus the edge clearance from
     the outline. The exact check used the via's square, whose corner reaches
     past a 45-degree chamfer where the round via does not."""
-    from freeroute.board.outline import BoardOutline
-    from freeroute.geometry import IntBox, IntPoint
-    from freeroute.route.exact_router import _inside_outline
+    from rpmroute.board.outline import BoardOutline
+    from rpmroute.geometry import IntBox, IntPoint
+    from rpmroute.route.exact_router import _inside_outline
 
     # a 10 mm square with its lower-left corner cut at 45 degrees
     outline = BoardOutline([IntPoint(*p) for p in