Add XIC v1 Engine — Execute-In-Compressed Runtime Integration

- Implemented XIC loader, VM, ops, and executor
- Wired RUN_PROMPT directly to execute_gx() (no stubs)
- Added demo compressed model and demo XIC program
- Integrated XIC into glyph_runner.py with --xic flag and shell support
- Added full validation suite and XIC_INTEGRATION_REPORT.md
- Verified real GSZ3 decompression and execution pipeline

This commit introduces a complete compressed-space execution engine
with zero breaking changes and full backward compatibility.

xic_loader.py

@@ -0,0 +1,66 @@
+import json
+from dataclasses import dataclass
+from typing import List, Dict, Any
+from pathlib import Path
+
+
+@dataclass
+class XICInstruction:
+    op: str
+    args: List[Any]
+
+
+@dataclass
+class XICProgram:
+    magic: str
+    version: int
+    model: str
+    entrypoint: str
+    symbols: Dict[str, int]
+    instructions: List[XICInstruction]
+
+
+class XICLoadError(Exception):
+    pass
+
+
+def load_xic(path: str) -> XICProgram:
+    """Load and validate an XIC program from JSON."""
+    try:
+        p = Path(path)
+        if not p.exists():
+            raise XICLoadError(f"File not found: {path}")
+
+        with open(p) as f:
+            data = json.load(f)
+
+        # Validate magic and version
+        magic = data.get("magic")
+        if magic != "GXIC1":
+            raise XICLoadError(f"Invalid magic: {magic} (expected GXIC1)")
+
+        version = data.get("version")
+        if version != 1:
+            raise XICLoadError(f"Unsupported version: {version}")
+
+        # Parse instructions
+        instructions = []
+        for instr in data.get("instructions", []):
+            instructions.append(XICInstruction(
+                op=instr["op"],
+                args=instr.get("args", [])
+            ))
+
+        return XICProgram(
+            magic=magic,
+            version=version,
+            model=data.get("model", ""),
+            entrypoint=data.get("entrypoint", "main"),
+            symbols=data.get("symbols", {}),
+            instructions=instructions
+        )
+
+    except json.JSONDecodeError as e:
+        raise XICLoadError(f"Invalid JSON: {e}")
+    except Exception as e:
+        raise XICLoadError(f"Load failed: {e}")