feat(cli): install in one command, and call the CLI ludic

Getting started meant cloning the repository, bootstrapping a compiler and
learning a task runner called `x`. That is a contributor's workflow handed to
everyone who wants to try the language.

Installing is now one command:

    curl -fsSL https://workshopsoft.pages.workshopsoft.io/ludic/install.sh | sh

install.sh puts a complete toolchain — compiler, CLI, engine runtime, bundled
ludic.* packages, formatter, language server — in ~/.ludic and adds it to PATH.
Prebuilt artifacts are checksum-verified; where a platform has none, or the
release predates this layout, it bootstraps from the compiler's own IR seed with
clang. The docs site publishes the script beside the pages that quote it, so the
page and the script can never come from different releases.

`x` becomes `ludic`, and the surface splits by audience. A user of the language
sees `new`, `run`, `build`, `test`, `add`, `fmt`, `lsp`, `doctor`, `upgrade`;
`ludic new` scaffolds a project that builds and plays as it stands. Everything
the toolchain repo needs moved under `ludic dev` — build, test, reseed,
bootstrap-cfree, docs-gen, release — unchanged apart from the namespace. Those
tasks read arguments one position further along, so dispatch_dev sets a shift
and commands use arg_n()/arg_total() rather than each knowing its own depth.

Release artifacts become complete install roots (bin/ beside runtime/, packages/
and VERSION) rather than bare binaries, which is what the installer unpacks.
`ludic dev test` asserts the whole shape: it stages an install, puts it on PATH
with no LUDIC_HOME, and runs new -> build -> test through it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.forgejo/workflows/release.yml

@@ -1,6 +1,6 @@
 name: release
 
-# Cutting a release is `x release` + `git push --tags`; everything after that
+# Cutting a release is `ludic dev release` + `git push --tags`; everything after that
 # happens here. Before this workflow existed the artifacts were built on whatever
 # machine the maintainer happened to be sitting at, from whatever was in bin/ at
 # the time, with no checksums and nothing proving the tagged tree even passed its
@@ -71,15 +71,15 @@ jobs:
           set -eu
           mkdir -p bin
           clang-16 tools/ci/linux_stdio_shim.ll selfhost/ludicc.seed.ll -o bin/ludicc
-          bin/ludicc tools/x/main.ludic -o bin/x
-          bin/x build
+          bin/ludicc tools/ludic-cli/main.ludic -o bin/ludic
+          bin/ludic dev build
 
       - name: The tagged tree must pass its own suites
         run: |
           set -eu
-          bin/x test
-          bin/x test-tools
-          bin/x bootstrap-cfree
+          bin/ludic dev test
+          bin/ludic dev test-tools
+          bin/ludic dev bootstrap-cfree
 
       - name: Publish the release
         env:
@@ -91,9 +91,9 @@ jobs:
             echo "::error::No FORGEJO_TOKEN secret; cannot create the release."
             exit 1
           fi
-          # x publish builds dist/ (source tarball from the tag, this host's
+          # ludic dev publish builds dist/ (source tarball from the tag, this host's
           # toolchain, SHA256SUMS), takes the notes from the CHANGELOG section,
           # and creates the release. Re-running it only adds missing assets, so
           # a maintainer can afterwards attach the macOS toolchain from a Mac
           # with the same command.
-          bin/x publish "$TAG"
+          bin/ludic dev publish "$TAG"