Stage 5: Alembic migrations, durable call rows, one transcript truth

Alembic replaces create_all as the schema authority: async env.py
against Base.metadata (CLI and in-app entry paths share it via
config.attributes["connection"]), an autogenerated baseline of the
create_all-era schema, and init_db now runs upgrade head — stamping
the baseline first on a pre-Alembic database so existing deployments
adopt cleanly. create_all remains for tests only.

Calls are durable from the start: CallManager gains an
on_call_created hook (wired to persist_call_on_create) that inserts
an in_progress CallRecord the moment a call is created;
persist_call_on_end finalizes that same row. A SIGKILL mid-call now
leaves an in_progress row instead of erasing the call from history
(verified live against the dev database).

One transcript representation: ActiveCall.transcript_chunks holds
TranscriptEntry (t_offset_ms, speaker, text) — add_transcript stamps
real offsets from connect time, receptionist passes speaker instead
of encoding it into "caller: ..." strings, persisted chunks carry
real seek offsets, and the dead CallRecord.transcript Text column is
dropped by migration. Device.is_online migrates String → Boolean
(with a USING cast for existing rows).

Model de-triplication: CallResponse/CallStatusResponse build via
from_call classmethods (one ActiveCall→response mapping);
DeviceStatus deleted — can_receive_call is a computed field on
Device and the list endpoint returns the domain model; all row↔dict
and row↔domain mapping now lives in call_persistence.py
(record_summary/record_detail/chunk_to_dict + device row functions).

New tests/test_data_layer.py: upgrade-head-matches-models,
pre-Alembic adoption, durable in_progress rows, end-without-create
fallback, transcript offsets, consolidated response models.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

models/call.py

@@ -55,6 +55,14 @@ class ClassificationResult(BaseModel):
     details: Optional[dict] = None  # Extra analysis data
 
 
+class TranscriptEntry(BaseModel):
+    """One transcribed utterance, offset from call start for seek."""
+
+    t_offset_ms: int
+    speaker: str = "unknown"  # caller / agent / receptionist / unknown
+    text: str
+
+
 class ActiveCall(BaseModel):
     """In-memory state for an active call."""
 
@@ -71,7 +79,7 @@ class ActiveCall(BaseModel):
     hold_started_at: Optional[datetime] = None
     current_classification: AudioClassification = AudioClassification.UNKNOWN
     classification_history: list[ClassificationResult] = Field(default_factory=list)
-    transcript_chunks: list[str] = Field(default_factory=list)
+    transcript_chunks: list[TranscriptEntry] = Field(default_factory=list)
     current_step_id: Optional[str] = None  # Current position in call flow
     services: list[str] = Field(default_factory=list)  # Active services on this call
 
@@ -92,7 +100,7 @@ class ActiveCall(BaseModel):
     @property
     def transcript(self) -> str:
         """Full transcript so far."""
-        return "\n".join(self.transcript_chunks)
+        return "\n".join(e.text for e in self.transcript_chunks)
 
     def summary(self) -> dict:
         """Compact summary for list views."""
@@ -145,6 +153,16 @@ class CallResponse(BaseModel):
     mode: str
     message: Optional[str] = None
 
+    @classmethod
+    def from_call(cls, call: "ActiveCall", message: Optional[str] = None) -> "CallResponse":
+        return cls(
+            call_id=call.id,
+            status=call.status.value,
+            number=call.remote_number,
+            mode=call.mode.value,
+            message=message,
+        )
+
 
 class CallStatusResponse(BaseModel):
     """Full status of an active or completed call."""
@@ -163,6 +181,25 @@ class CallStatusResponse(BaseModel):
     current_step: Optional[str] = None
     services: list[str] = Field(default_factory=list)
 
+    @classmethod
+    def from_call(cls, call: "ActiveCall") -> "CallStatusResponse":
+        """The one ActiveCall → status-response mapping."""
+        return cls(
+            call_id=call.id,
+            status=call.status.value,
+            direction=call.direction,
+            remote_number=call.remote_number,
+            mode=call.mode.value,
+            duration=call.duration,
+            hold_time=call.hold_time,
+            audio_type=call.current_classification.value,
+            intent=call.intent,
+            transcript_excerpt=call.transcript[-500:] if call.transcript else None,
+            classification_history=call.classification_history[-20:],
+            current_step=call.current_step_id,
+            services=call.services,
+        )
+
 
 class TransferRequest(BaseModel):
     """Request to transfer a call to a device."""