fix: live flow real-time updates during processing (#861)

* fix: live flow real-time updates during processing

Three gaps caused transcript pages to require manual refresh after
live recording/processing:

1. UserEventsProvider only invalidated list queries on TRANSCRIPT_STATUS,
   not individual transcript queries. Now parses data.id from the event
   and calls invalidateTranscript for the specific transcript.

2. useWebSockets had no reconnection logic — a dropped WS silently
   killed all real-time updates. Added exponential backoff reconnection
   (1s-30s, max 10 retries) with intentional close detection.

3. No polling fallback — WS was single point of failure. Added
   conditional refetchInterval to useTranscriptGet that polls every 5s
   when transcript status is processing/uploaded/recording.

* feat: type-safe WebSocket events via OpenAPI stub

Define Pydantic models with Literal discriminators for all WS events
(9 transcript-level, 5 user-level). Expose via stub GET endpoints so
pnpm openapi generates TS discriminated unions with exhaustive switch
narrowing on the frontend.

- New server/reflector/ws_events.py with TranscriptWsEvent and UserWsEvent
- Tighten backend emit signatures with TranscriptEventName literal
- Frontend uses generated types, removes Zod schema and manual casts
- Fix pre-existing bugs: waveform mapping, FINAL_LONG_SUMMARY field name
- STATUS value now typed as TranscriptStatus literal end-to-end
- TOPIC handler simplified to query invalidation only (avoids shape mismatch)

* fix: restore TOPIC WS handler with immediate state update

The setTopics call provides instant topic rendering during live
transcription. Query invalidation still follows for full data sync.

* fix: align TOPIC WS event data with GetTranscriptTopic shape

Convert TranscriptTopic → GetTranscriptTopic in pipeline before
emitting, so WS sends segments instead of words. Removes the
`as unknown as Topic` cast on the frontend.

* fix: use NonEmptyString and TranscriptStatus in user WS event models

---------

Co-authored-by: Igor Loskutov <igor.loskutoff@gmail.com>

server/reflector/db/transcripts.py

@@ -5,7 +5,10 @@ import shutil
 from contextlib import asynccontextmanager
 from datetime import datetime, timedelta, timezone
 from pathlib import Path
-from typing import Any, Literal, Sequence
+from typing import TYPE_CHECKING, Any, Literal, Sequence
+
+if TYPE_CHECKING:
+    from reflector.ws_events import TranscriptEventName
 
 import sqlalchemy
 from fastapi import HTTPException
@@ -184,7 +187,7 @@ class TranscriptWaveform(BaseModel):
 
 
 class TranscriptEvent(BaseModel):
-    event: str
+    event: str  # Typed at call sites via ws_events.TranscriptEventName; str here for DB compat
     data: dict
 
 
@@ -233,7 +236,9 @@ class Transcript(BaseModel):
             dt = dt.replace(tzinfo=timezone.utc)
         return dt.isoformat()
 
-    def add_event(self, event: str, data: BaseModel) -> TranscriptEvent:
+    def add_event(
+        self, event: "TranscriptEventName", data: BaseModel
+    ) -> TranscriptEvent:
         ev = TranscriptEvent(event=event, data=data.model_dump())
         self.events.append(ev)
         return ev
@@ -688,7 +693,7 @@ class TranscriptController:
     async def append_event(
         self,
         transcript: Transcript,
-        event: str,
+        event: "TranscriptEventName",
         data: Any,
     ) -> TranscriptEvent:
         """