feat: complete Phase 1 - vocabulary expansion & DriftProbe infrastructure

- CLI: nyx-probe scan with --summary/--delta/--full flags
- DriftProbe: training safety with Gini coefficient + Angular Drift
- Vocabulary: 54 terms (30 nimmerverse + 24 German philosophical)
- Sentinels: ANCHOR/BRIDGE/CANARY/TARGET monitoring system

Key findings:
- German philosophical terms: 37.5% depth≥2 hit rate (vs 3.3% nimmerverse)
- Super Cluster validated: heart cross-lang sim = 1.000
- Isolated Zone confirmed: being EN↔DE sim = 0.195
- Gini signature: Philosophy ~0.5 (diffuse), Technical ~0.8 (sparse)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

nyx_probing/probes/base.py

@@ -0,0 +1,58 @@
+"""
+Base class for all probes.
+
+Probes are measurement instruments - they reveal what's already there,
+they don't add or change anything.
+"""
+from abc import ABC, abstractmethod
+from typing import Any
+from ..core.model import NyxModel
+
+
+class BaseProbe(ABC):
+    """Abstract base class for probing operations."""
+
+    def __init__(self, model: NyxModel):
+        """
+        Initialize probe with a loaded model.
+
+        Args:
+            model: A NyxModel instance (must be loaded)
+        """
+        self.model = model
+        if not model._loaded:
+            raise ValueError("Model must be loaded before creating probe")
+
+    @property
+    def name(self) -> str:
+        """Name of this probe type."""
+        return self.__class__.__name__
+
+    @abstractmethod
+    def probe(self, term: str, **kwargs) -> Any:
+        """
+        Probe a single term.
+
+        Args:
+            term: The word/phrase to probe
+            **kwargs: Probe-specific parameters
+
+        Returns:
+            Probe-specific result object
+        """
+        pass
+
+    def probe_batch(self, terms: list[str], **kwargs) -> list[Any]:
+        """
+        Probe multiple terms.
+
+        Default implementation just loops; subclasses can optimize.
+
+        Args:
+            terms: List of words/phrases to probe
+            **kwargs: Probe-specific parameters
+
+        Returns:
+            List of probe results
+        """
+        return [self.probe(term, **kwargs) for term in terms]