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_fixed_wiring.py

@@ -2,9 +2,9 @@
 
 from __future__ import annotations
 
-from freeroute.board import build_board
-from freeroute.dsn import parse_dsn
-from freeroute.route.pipeline import route_dsn_board_exact
+from rpmroute.board import build_board
+from rpmroute.dsn import parse_dsn
+from rpmroute.route.pipeline import route_dsn_board_exact
 
 _DSN = """(pcb wired (parser) (resolution um 10) (unit um)
   (structure
@@ -95,9 +95,9 @@ def test_a_fanned_out_signal_is_routed_from_its_via():
 
 def test_the_session_never_repeats_copper_already_on_the_board():
     # the JAR writes the DSN's wiring back into its session, and an applier
-    # then adds it a second time on top of itself; freeroute writes only
+    # then adds it a second time on top of itself; rpmroute writes only
     # what it routed
-    from freeroute.route.pipeline import build_exact_routing_result
+    from rpmroute.route.pipeline import build_exact_routing_result
 
     fixed_vias = {(5000.0, -11500.0), (10000.0, -11500.0)}
     fixed_paths = {(5000.0, -10000.0, 5000.0, -11500.0), (10000.0, -10000.0, 10000.0, -11500.0),