fix(newos4): coreutils flags + loop-guard arg key, both found by the agent's live run (v4.6.49)

Agent session surfaced two real defects:

1. The A4 prompt told it to use grep -n / sed -n 'N,Mp' / wc -l / head -N — none of those flags
   parsed: grep treated '-n' as the pattern (6/6 variants failed), wc read '-l' as a filename,
   head looked for a file named '-2', sed had no range parser. Fixed the tools, not just the text:
   grep now accepts -n/-i/-c/-v/-l (line numbers were already printed), wc accepts -l/-w/-c,
   head accepts -N and -n N, sed accepts Np and N,Mp, tail no longer prints a blank line for a
   trailing newline. Prompt re-ranked to the working forms.

2. Loop guard keyed calls by tool name plus the raw arguments field. When arguments was already
   an object (parsed upstream), the key became 'run_command:[object Object]', collapsing distinct
   batched commands into one signature and producing false "called 3x" warnings. Now the key is
   JSON.stringify(arguments) whenever it is not a string (3 sites: sig, _sigR, _sigD).

Verified live v4.6.49: grep -n/-c, wc -l, head -2, sed -n '2,3p', tail -n 1 all correct.

1 files changed, 1 insertions, 1 deletions

diff --git a/modules/core/module-loader.js b/modules/core/module-loader.js
index ccd92d8..8330eaf 100644
--- a/modules/core/module-loader.js
+++ b/modules/core/module-loader.js
@@ -4,7 +4,7 @@
     // Core module bundle loaded synchronously in main.html.
     // This loader only handles version cache-busting, splash, terminal init, and optional ext modules.
 
-    const LATEST_VER = 'v4.6.47';
+    const LATEST_VER = 'v4.6.49';
     const CACHE = '?v=' + LATEST_VER;
     const stored = localStorage.getItem('webx11_cache_ver');
     if (stored !== LATEST_VER) {