feat: add call history API endpoints and TTS service client

Adds read-only access to persisted call records for the dashboard
and implements a client for the Rhema text-to-speech service.

- api/call_history.py: New router providing paged call lists
  and detailed call records with transcript metadata.
- services/tts.py: Async client for OpenAI-compatible TTS
  endpoints (Rhema/Kokoro) used for call-flow steps.

db/database.py

@@ -8,6 +8,7 @@ from datetime import datetime
 
 from sqlalchemy import (
     JSON,
+    Boolean,
     Column,
     DateTime,
     Float,
@@ -111,6 +112,7 @@ class Device(Base):
     priority = Column(Integer, default=10)  # Routing priority (lower = higher priority)
     is_online = Column(String, default="false")
     capabilities = Column(JSON, default=list)  # ["voice", "video", "sms"]
+    dnd = Column(Boolean, default=False, nullable=False)
     last_seen = Column(DateTime, nullable=True)
     created_at = Column(DateTime, default=func.now())
     updated_at = Column(DateTime, default=func.now(), onupdate=func.now())
@@ -119,6 +121,55 @@ class Device(Base):
         return f"<Device {self.id} {self.name} ({self.type})>"
 
 
+class RoutingRuleRecord(Base):
+    __tablename__ = "routing_rules"
+
+    id = Column(String, primary_key=True)
+    name = Column(String, nullable=False)
+    priority = Column(Integer, default=100, nullable=False)  # lower runs first
+    enabled = Column(Boolean, default=True, nullable=False)
+    match = Column(JSON, nullable=False)  # caller_pattern, dnis, time_range, days
+    action = Column(JSON, nullable=False)  # {type, ...}
+    created_at = Column(DateTime, default=func.now())
+    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())
+
+    def __repr__(self) -> str:
+        return f"<RoutingRule {self.id} {self.name} p={self.priority}>"
+
+
+class TranscriptChunk(Base):
+    __tablename__ = "transcript_chunks"
+
+    id = Column(String, primary_key=True)
+    call_id = Column(String, index=True, nullable=False)
+    seq = Column(Integer, nullable=False)
+    t_offset_ms = Column(Integer, default=0)  # offset from call start
+    speaker = Column(String, default="unknown")  # caller / agent / receptionist / unknown
+    text = Column(Text, nullable=False)
+    confidence = Column(Float, nullable=True)
+    created_at = Column(DateTime, default=func.now())
+
+    def __repr__(self) -> str:
+        return f"<TranscriptChunk {self.call_id}#{self.seq}>"
+
+
+class RecordingRecord(Base):
+    __tablename__ = "recordings"
+
+    id = Column(String, primary_key=True)
+    call_id = Column(String, index=True, nullable=False)
+    path = Column(String, nullable=False)
+    format = Column(String, default="wav")
+    duration_s = Column(Float, default=0.0)
+    size_bytes = Column(Integer, default=0)
+    channels = Column(Integer, default=1)
+    started_at = Column(DateTime, default=func.now())
+    ended_at = Column(DateTime, nullable=True)
+
+    def __repr__(self) -> str:
+        return f"<Recording {self.id} call={self.call_id} {self.path}>"
+
+
 # ============================================================
 # Engine & Session
 # ============================================================