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_router.py

@@ -16,11 +16,11 @@ import sys
 
 import pytest
 
-from freeroute.board import build_board
-from freeroute.dsn import parse_dsn
-from freeroute.dsn.sexp import parse
-from freeroute.route import route, route_dsn_board
-from freeroute.ses.writer import ses_scale
+from rpmroute.board import build_board
+from rpmroute.dsn import parse_dsn
+from rpmroute.dsn.sexp import parse
+from rpmroute.route import route, route_dsn_board
+from rpmroute.ses.writer import ses_scale
 
 sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
 
@@ -287,11 +287,11 @@ def test_connectivity_parity_on_congested_board():
     if not HAS_ORACLE:
         pytest.skip("FreeRouting oracle unavailable")
     our_nets = routed_net_set(route(RIPUP.read_text()))
-    assert our_nets == {"NET_A", "NET_B"}  # freeroute connects both via rip-up
+    assert our_nets == {"NET_A", "NET_B"}  # rpmroute connects both via rip-up
     oracle_nets = routed_net_set(route_dsn(RIPUP, max_passes=3, timeout=300))
     if not oracle_nets:
         # the reference JAR does not route this synthetic single-signal-layer
-        # board (it expects a routing/via layer); freeroute's rip-up connecting
+        # board (it expects a routing/via layer); rpmroute's rip-up connecting
         # both nets is already asserted above and by the fast tests.
         pytest.skip("reference JAR routed nothing on the synthetic single-layer board")
     assert oracle_nets <= our_nets  # rip-up matches the JAR's connectivity
@@ -306,7 +306,7 @@ def test_connectivity_parity_on_crossing_board():
     our_nets = routed_net_set(route(CROSSING.read_text()))
     oracle_nets = routed_net_set(route_dsn(CROSSING, max_passes=3, timeout=300))
     assert oracle_nets, "oracle routed nothing on a routable board"
-    assert oracle_nets <= our_nets  # freeroute connects every net the JAR does
+    assert oracle_nets <= our_nets  # rpmroute connects every net the JAR does
 
 
 @pytest.mark.oracle