fix(scripts): kevin-analyze + reanalyze — self-contained + append-only

Two small follow-ups from the session:

- kevin-analyze.sh: always cp the local analyze_kevin_video.py into
  the pod before exec, so the wrapper works even before CI ships an
  image with scripts/ baked in (saw this hit the user with
  ModuleNotFoundError on stale images).

- reanalyze_kevin_videos.py: switch from DELETE+INSERT to
  append-only. The old behaviour violated the FK constraint on
  kevin_signal_bridge_state.mention_id; the new behaviour adds a
  fresh v2 analysis alongside the v1 row and lets the API surface
  the latest. Old v1 rows preserved for audit.

scripts/kevin-analyze.sh

@@ -5,8 +5,9 @@
 #   ./scripts/kevin-analyze.sh <video-id-or-url>
 #
 # Picks the running meet-kevin-watcher container (which already has
-# yt-dlp + ffmpeg + the Anthropic token + the right Python env) and
-# runs scripts/analyze_kevin_video.py inside it.
+# yt-dlp + ffmpeg + the Anthropic token + the right Python env), copies
+# the local script in, and runs it. Works regardless of whether the
+# image has scripts/ baked in yet.
 
 set -euo pipefail
 
@@ -15,6 +16,14 @@ if [[ $# -ne 1 ]]; then
     exit 1
 fi
 
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+LOCAL_SCRIPT="$SCRIPT_DIR/analyze_kevin_video.py"
+
+if [[ ! -f "$LOCAL_SCRIPT" ]]; then
+    echo "missing $LOCAL_SCRIPT" >&2
+    exit 1
+fi
+
 POD=$(kubectl -n trading-bot get pod -l app=trading-bot-workers \
     -o jsonpath='{.items[0].metadata.name}')
 
@@ -23,5 +32,10 @@ if [[ -z "$POD" ]]; then
     exit 1
 fi
 
+# Copy the latest local script into the pod, then exec it. This way the
+# wrapper works even before CI ships an image with scripts/ baked in.
+kubectl -n trading-bot cp "$LOCAL_SCRIPT" \
+    "$POD:/tmp/kevin-analyze.py" -c meet-kevin-watcher >/dev/null
+
 exec kubectl -n trading-bot exec "$POD" -c meet-kevin-watcher -- \
-    python -m scripts.analyze_kevin_video "$1"
+    python /tmp/kevin-analyze.py "$1"

scripts/reanalyze_kevin_videos.py

@@ -29,7 +29,7 @@ from anthropic import AsyncAnthropic
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-from sqlalchemy import delete, select
+from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from services.meet_kevin_watcher.caption_extractor import extract_captions
@@ -86,14 +86,11 @@ async def _reanalyze_one(
     if dry_run:
         return True, result.cost_usd, "dry_run_skipped_write"
 
-    # Replace old analysis + mentions for this video atomically.
-    await session.execute(
-        delete(KevinStockMention).where(KevinStockMention.video_id == video.id)
-    )
-    await session.execute(
-        delete(KevinAnalysis).where(KevinAnalysis.video_id == video.id)
-    )
-
+    # Append-only: insert new analysis + mentions for this video. We do
+    # NOT delete the old v1 rows because kevin_signal_bridge_state has
+    # FKs into kevin_stock_mentions (would cascade-break the audit
+    # trail). The API surfaces the newest analysis per video and the
+    # bridge picks up the new mentions by ID > cursor.
     db_analysis = KevinAnalysis(
         video_id=video.id,
         model=analyzer._model,