lexer: strip JS/CSS comments from code-bearing string literals at compile time

scan_string() is the right gate for this: every El source that embeds JS
or CSS does so as a quoted string literal, and the lexer is the single
chokepoint every backend reads. Strip there and the // line comments
and /* */ block comments never reach the parser, codegen, or the served
HTML.

looks_like_code is intentionally narrow:
  - contains "<script" or "<style" (the embedded-asset case), or
  - contains "function" AND ";" (a JS body without an opening tag)
Plain prose with stray // sequences passes through verbatim.

strip_code_comments tracks JS string state (single, double, backtick)
and never strips inside one. Backslash escapes inside JS strings consume
the next char verbatim. URL guard: when the char before / is ':', emit
the / literally and advance one — preserves https:// inside string
literals. Block-comment scan walks until the matching '*/' pair.

elc-cli.el is now a one-line `import "el-compiler/src/compiler.el"`
shim. Top-level `let _argv = args()` was clashing with C int main()'s
`char** _argv` parameter once compiler.el's fn main() body got folded
into C main. compiler.el owns the CLI entry point now.

Self-host fixed point reached: gen2 == gen3 byte-identical.
Tagged dist/platform/elc.20260502-1104-self-host alongside dist/platform/elc.

elc-cli.el

@@ -1,8 +1,7 @@
+// elc-cli.el — entry point for the self-hosted el compiler.
+//
+// All logic lives in el-compiler/src/compiler.el (which defines fn main()).
+// Importing it pulls in compiler.el + parser + lexer + codegen transitively.
+// The native compiler resolves imports textually and folds fn main() into
+// C's int main(), so this file does not declare any top-level work itself.
 import "el-compiler/src/compiler.el"
-
-// compile() streams C source to stdout via println.
-// We read source from args()[0] and compile it.
-let _argv: [String] = args()
-let src_path: String = native_list_get(_argv, 0)
-let source: String = fs_read(src_path)
-compile(source)