build(x): stop printing a clang warning on every build

Each clang invocation the task runner makes emitted

    warning: overriding the module target triple with arm64-apple-macosx15.5.0

four times per `x build`, with nothing for anyone to act on. `cc()` now passes
-Wno-override-module, the same flag ludicc already passes for its own link.

The comment in selfhost/main.ludic explaining that flag had it backwards — it
claimed "our IR carries an explicit target triple", when the emitted IR names
no triple at all, which is precisely why clang substitutes the host's and
warns. Corrected. No IR changes, so the seed is untouched.

Also adds .claude/launch.json entry for previewing the generated docs locally.

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

tools/x/selfhost.ludic

@@ -6,7 +6,10 @@
 # now lives here once, in selfhost_frags().
 
 # the C toolchain driver (clang) that assembles and links the emitted IR
-function cc() -> pointer { return getenv_or("LUDIC_CC", "clang") }
+# The C toolchain used to assemble and link IR. -Wno-override-module for the
+# same reason the compiler itself passes it (see selfhost/main.ludic): the IR
+# names no target triple, so clang substitutes the host's and warns every time.
+function cc() -> pointer { return getenv_or("LUDIC_CC", "clang") + " -Wno-override-module" }
 
 # the self-host compiler's source fragments, in link order. This is THE list;
 # the old scripts each carried their own copy.