fix(frida): share exact JSON string byte accounting

Count the serialized JSON representation at its owner, including escaped
lone UTF-16 surrogates. Frida now retains the correct bounded prefix and
reports truncation in script results and subsequent session Evidence.

Move the existing exact managed string counter into the domain layer and
use it for Frida, managed projections and Ghidra inline PDB caveats. Remove
the superseded counters while keeping Ghidra's bounded length guards and
NativeAOT's distinct raw-byte admission before string allocation.

Validated with 296 focused tests, check, docs and exact test discovery.
The Unicode oracle checks every UTF-16 code unit and adjacent fragments
against native JSON encoding. Frida execution uses simulated native handles
through the real MCP handlers/client; real target instrumentation is unverified.

Fixes #5097

Co-authored-by: Prabhuram Karki <prabhuramkarki07@gmail.com>

src/domain/jsonStringByteLength.ts

@@ -0,0 +1,28 @@
+/** Exact UTF-8 bytes of a JSON string literal, counted without serializing it. */
+export const jsonStringByteLength = (value: string): number => {
+  let bytes = 2;
+  for (let index = 0; index < value.length; index++) {
+    const unit = value.charCodeAt(index);
+    if (unit === 0x22 || unit === 0x5c) bytes += 2;
+    else if (unit < 0x20)
+      bytes +=
+        unit === 0x08 ||
+        unit === 0x09 ||
+        unit === 0x0a ||
+        unit === 0x0c ||
+        unit === 0x0d
+          ? 2
+          : 6;
+    else if (unit < 0x80) bytes += 1;
+    else if (unit < 0x800) bytes += 2;
+    else if (unit >= 0xd800 && unit <= 0xdbff) {
+      const next = value.charCodeAt(index + 1);
+      if (next >= 0xdc00 && next <= 0xdfff) {
+        bytes += 4;
+        index++;
+      } else bytes += 6;
+    } else if (unit >= 0xdc00 && unit <= 0xdfff) bytes += 6;
+    else bytes += 3;
+  }
+  return bytes;
+};