add Signal command and control bot service

Python service for jeeves that communicates over Signal via signal-cli-rest-api.
Implements device verification via safety numbers (unverified devices cannot
run commands until verified over SSH), and a van inventory command that uses
an LLM on BOB (ollama) to parse receipt photos or text lists into structured
inventory data. The LLM backend is configurable to swap models easily.

https://claude.ai/code/session_01AKXQBuVBsW7J1YbukDiQ7A

python/signal_bot/models.py

@@ -0,0 +1,86 @@
+"""Models for the Signal command and control bot."""
+
+from __future__ import annotations
+
+from datetime import datetime  # noqa: TC003 - pydantic needs this at runtime
+from enum import StrEnum
+from typing import Any
+
+from pydantic import BaseModel
+
+
+class TrustLevel(StrEnum):
+    """Device trust level."""
+
+    VERIFIED = "verified"
+    UNVERIFIED = "unverified"
+    BLOCKED = "blocked"
+
+
+class Device(BaseModel):
+    """A registered device tracked by safety number."""
+
+    phone_number: str
+    safety_number: str
+    trust_level: TrustLevel = TrustLevel.UNVERIFIED
+    first_seen: datetime
+    last_seen: datetime
+
+
+class SignalMessage(BaseModel):
+    """An incoming Signal message."""
+
+    source: str
+    timestamp: int
+    message: str = ""
+    attachments: list[str] = []
+    group_id: str | None = None
+    is_receipt: bool = False
+
+
+class SignalEnvelope(BaseModel):
+    """Raw envelope from signal-cli-rest-api."""
+
+    envelope: dict[str, Any]
+    account: str | None = None
+
+
+class InventoryItem(BaseModel):
+    """An item in the van inventory."""
+
+    name: str
+    quantity: int = 1
+    category: str = ""
+    notes: str = ""
+
+
+class InventoryUpdate(BaseModel):
+    """Result of processing an inventory update."""
+
+    items: list[InventoryItem] = []
+    raw_response: str = ""
+    source_type: str = ""  # "receipt_photo" or "text_list"
+
+
+class LLMConfig(BaseModel):
+    """Configuration for an LLM backend."""
+
+    model: str
+    host: str
+    port: int = 11434
+    temperature: float = 0.1
+
+    @property
+    def base_url(self) -> str:
+        """Ollama API base URL."""
+        return f"http://{self.host}:{self.port}"
+
+
+class BotConfig(BaseModel):
+    """Top-level bot configuration."""
+
+    signal_api_url: str
+    phone_number: str
+    llm: LLMConfig
+    poll_interval: int = 2
+    inventory_file: str = "van_inventory.json"