Baseline: Ludic compiler + toolchain, Phase 1 syntax fixes complete

Self-hosted compiler (selfhost/*.ludic), runtime, examples, editor tooling,
and docs. Phase 1 of the syntax-redesign cohesion pass has landed:
edge-system fix, signature-query, when-alias, and the documentation truth-pass.
Suite green (14/14), C-free bootstrap fixpoint holds.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

selfhost/io.ludic

@@ -0,0 +1,22 @@
+# io.ludic — reading the input file and writing the output, plus tiny stdio.
+# The compiler reads one .ludic file whole and emits LLVM IR text to stdout.
+
+fn read_file(path: str) -> ptr {
+  let f = file_open(path, "rb")
+  if ptr_is_null(f) { return ptr_null() }
+  file_seek(f, 0, 2)
+  let n = file_tell(f)
+  file_seek(f, 0, 0)
+  let buf = mem_alloc(n + 1)
+  file_read(f, buf, n)
+  poke8(buf, n, 0)
+  file_close(f)
+  return buf
+}
+
+# length of a NUL-terminated buffer
+fn cstr_len(s: ptr) -> int {
+  let n = 0
+  while peek8(s, n) != 0 { n = n + 1 }
+  return n
+}