refactor(x): per-process scratch dirs, Ludic ports of the LSP test and Forgejo release

- every scratch file lives in `$TMPDIR/x_<pid>/` (tmp_dir/tmp_path in
  prelude.ludic), removed by main's new dispatch() → tmp_cleanup();
  X_KEEP_TMP=1 keeps it. `x test` and `x check-*` may now run together.
- `x test-lsp` (tools/x/lsp_test.ludic) replaces tools/test-lsp.py: the
  whole request stream is framed into one stdin file, the server runs to
  `exit`, and the response stream is parsed back by request id; adds a
  check that ludicc's own error is published on save
- tools/x/forgejo.ludic replaces tools/ci/forgejo_release.py (curl with a
  0600 header file; the token is no longer on the command line;
  LUDIC_FORGEJO_API for forks)
- `x docs-palette --check` regenerates into scratch and compares, so the
  drift guard judges the working tree rather than git HEAD; the generator
  no longer emits a trailing blank line the formatter rejects
- `x test-tools`: exit 2 from test-lsp / test-grammar.js is a visible
  skip, never a pass; the widget-prop test uses the `id: Root` syntax
- tools/test-grammar.js: current vocabulary (property/model/handler/
  prefab/scene/event/become/@Queries), LUDIC_NODE_MODULES, exit 2 on skip
- tools/atlas.ludic rewritten in the current language (it did not compile)
- operators.ludic / os.ludic registered in the suite
- json.ludic: j_quote() writer helper

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tools/x/prelude.ludic

@@ -49,9 +49,37 @@ function sh(cmd: pointer) -> int { return exit_code(run(cmd)) }
 # run a command, true when it succeeded
 function shq(cmd: pointer) -> bool { return exit_code(run(cmd)) == 0 }
 
+# ---- scratch files ------------------------------------------------------------
+# Every scratch file the runner writes lives under one per-process directory
+# (`$TMPDIR/x_<pid>`), so `x test` and an `x check-*` can run side by side without
+# clobbering each other's captures. main removes it on the way out.
+var x_tmp: pointer = null
+
+function tmp_dir() -> pointer {
+  if x_tmp == null {
+    var base = Os.temp_dir()
+    if len(base) > 1 and base[len(base) - 1] == '/' { base = base[0..len(base) - 1] }   # macOS: TMPDIR ends in '/'
+    x_tmp = `{base}/x_{Os.pid()}`
+    run(`mkdir -p {x_tmp}`)
+  }
+  return x_tmp
+}
+
+# a scratch path under tmp_dir(): tmp_path("foo.out")
+function tmp_path(name: pointer) -> pointer { return `{tmp_dir()}/{name}` }
+
+# remove the scratch directory (idempotent; a no-op when nothing was written).
+# X_KEEP_TMP=1 leaves it in place, and says where, for debugging a failing case.
+function tmp_cleanup() -> void {
+  if x_tmp == null { return }
+  if getenv_or("X_KEEP_TMP", "0") == "1" { print(`scratch kept: {x_tmp}`) }
+  else { run(`rm -rf {x_tmp}`) }
+  x_tmp = null
+}
+
 # run `cmd` and return its stdout (stderr discarded). Never null.
 function capture(cmd: pointer) -> pointer {
-  let tmp = "/tmp/x_capture.out"
+  let tmp = tmp_path("capture.out")
   run(`{cmd} > {tmp} 2>/dev/null`)
   let s = read_file(tmp)
   if (s == null) { return "" }
@@ -83,7 +111,7 @@ function flat(p: pointer) -> pointer {
   let b = bytes(n + 1)
   for i in 0 .. n {
     var c = p[i]
-    if (c == 47) { c = 95 }   # '/' (47) -> '_' (95)
+    if (c == '/') { c = 95 }   # '/' (47) -> '_' (95)
     b[i] = c
   }
   b[n] = 0
@@ -108,11 +136,11 @@ var PASS: int = 0
 var FAIL: int = 0
 
 function ok(msg: pointer) -> void {
-  PASS = PASS + 1
+  PASS += 1
   print(`  {c_green()}PASS{c_reset()} {msg}`)
 }
 function bad(msg: pointer) -> void {
-  FAIL = FAIL + 1
+  FAIL += 1
   print(`  {c_red()}FAIL{c_reset()} {msg}`)
 }
 function bad2(msg: pointer, detail: pointer) -> void {