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.

CLAUDE.md

@@ -1,12 +1,12 @@
 # CLAUDE.md
 
-Guidance for Claude Code working in the `freeroute` repository.
+Guidance for Claude Code working in the `rpmroute` repository.
 
 ## What this is
 
 A native Python PCB autorouter: a Java-free reimplementation of the
 [FreeRouting](https://github.com/freerouting/freerouting) engine. Specctra DSN
-in, Specctra SES out, no JVM anywhere. Published on PyPI as `freeroute`
+in, Specctra SES out, no JVM anywhere. Published on PyPI as `rpmroute`
 (GPL-3.0-or-later, CalVer).
 
 ## Commands
@@ -16,7 +16,7 @@ uv sync
 uv run pytest -m "not oracle"        # the fast suite (this is what you run)
 uv run pytest -m oracle              # differential tests against the real JAR (needs Java)
 uv run ruff check src/ tests/
-uv run freeroute board.dsn --engine room --pack -do board.ses
+uv run rpmroute board.dsn --engine room --pack -do board.ses
 ```
 
 ## The three non-negotiable invariants
@@ -67,7 +67,7 @@ route/     grid_router | exact_router | room_router, shove, pipeline, cli
   decomposed into convex rooms joined by doors, so it routes off-grid channels
   the grid literally cannot see. DRC-clean. Supports `--pack` and `--shove`.
 
-The engine/option matrix lives in `freeroute.cli.ENGINE_OPTIONS` and is
+The engine/option matrix lives in `rpmroute.cli.ENGINE_OPTIONS` and is
 importable, so consumers can assert against it. **An unsupported combination is
 a hard error (exit 2), never a silent no-op.** Downstream code (`mckicad`) reads
 this matrix to avoid sending an invalid pair.