refactor: move shared modules to core/, delete legacy code

Move to core/:
  config.py, database.py, repository.py, tables.py,
  id_gen.py, timezone.py, slack_log.py → core/

Delete legacy (unused):
  sheets/ — Google Sheets client + migrations (PG is sole DB)
  sync/ — Sheets→PG seed script (initial migration done)
  permission.py — replaced by SpiceDB authz
  tests/test_sheets_delete.py — tested deleted module

Remove from deploy.sh:
  Sheets→PG seed step (no longer exists)

Update all imports across 15+ files.
20 tests passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ImTotem

alembic/env.py

@@ -5,9 +5,9 @@
 
 from alembic import context
 
-from bcsd_api.config import Settings
-from bcsd_api.database import metadata
-import bcsd_api.tables  # noqa: F401 — registers tables on metadata
+from bcsd_api.core.config import Settings
+from bcsd_api.core.database import metadata
+import bcsd_api.core.tables  # noqa: F401 — registers tables on metadata
 
 config = context.config
 

infra/scripts/deploy.sh

@@ -88,13 +88,10 @@ $COMPOSE build "api-${NEXT}"
 echo "3. Running DB migrations..."
 $COMPOSE run --rm --no-deps "api-${NEXT}" alembic upgrade head
 
-echo "4. Seeding PG from Sheets (if empty)..."
-$COMPOSE run --rm --no-deps "api-${NEXT}" python -m bcsd_api.sync.seed
-
-echo "5. Starting $NEXT..."
+echo "4. Starting $NEXT..."
 $COMPOSE up -d --remove-orphans "api-${NEXT}"
 
-echo "6. Health check on api-${NEXT}..."
+echo "5. Health check on api-${NEXT}..."
 if ! health_check "$NEXT"; then
     echo "FAIL: $NEXT did not become healthy"
     echo "--- Container logs ---"
@@ -104,17 +101,17 @@ if ! health_check "$NEXT"; then
     exit 1
 fi
 
-echo "7. Switching nginx → $NEXT"
+echo "6. Switching nginx → $NEXT"
 sed -i "s/proxy_pass http:\/\/api_${CURRENT}/proxy_pass http:\/\/api_${NEXT}/g" "$NGINX_CONF"
 sudo mkdir -p /var/www/certbot
 sudo cp "$NGINX_CONF" "$NGINX_AVAILABLE"
 sudo ln -sf "$NGINX_AVAILABLE" "$NGINX_ENABLED"
 sudo nginx -t && sudo nginx -s reload
 
-echo "8. Stopping old ($CURRENT)..."
+echo "7. Stopping old ($CURRENT)..."
 $COMPOSE stop "api-${CURRENT}"
 
-echo "9. Initializing n8n..."
+echo "8. Initializing n8n..."
 bash infra/scripts/init_n8n.sh
 
 echo "=== Deploy complete: $NEXT is live ==="

src/bcsd_api/apply/pg_repository.py

@@ -1,7 +1,7 @@
 from sqlalchemy import Connection, insert, select, update
 
-from bcsd_api.repository import BaseRepository
-from bcsd_api.tables import application_answers, applications
+from bcsd_api.core.repository import BaseRepository
+from bcsd_api.core.tables import application_answers, applications
 
 
 class PgApplicationRepository(BaseRepository):

src/bcsd_api/apply/service.py

@@ -3,10 +3,10 @@
 
 from bcsd_api.exception import BadRequest, Conflict, Forbidden, NotFound
 from bcsd_api.form.pg_repository import PgFormRepository, PgQuestionRepository
-from bcsd_api.id_gen import generate_id
+from bcsd_api.core.id_gen import generate_id
 from bcsd_api.member.pg_repository import PgMemberRepository
 from bcsd_api.setting.pg_repository import PgSettingRepository
-from bcsd_api.timezone import KST
+from bcsd_api.core.timezone import KST
 
 from .pg_repository import PgAnswerRepository, PgApplicationRepository
 from .schema import (

src/bcsd_api/auth/router.py

@@ -1,7 +1,7 @@
 from fastapi import APIRouter, Depends, Response
 from sqlalchemy import Connection
 
-from bcsd_api.config import Settings
+from bcsd_api.core.config import Settings
 from bcsd_api.dependencies import (
     current_user, get_conn, get_email_sender, get_member_repo, get_settings,
 )

src/bcsd_api/auth/service.py

@@ -2,13 +2,13 @@
 
 from sqlalchemy import Connection, select
 
-from bcsd_api.config import Settings
+from bcsd_api.core.config import Settings
 from bcsd_api.email.sender import EmailSender
 from bcsd_api.exception import Conflict, Unauthorized
-from bcsd_api.id_gen import generate_id
+from bcsd_api.core.id_gen import generate_id
 from bcsd_api.member.pg_repository import PgMemberRepository
-from bcsd_api.tables import app_settings
-from bcsd_api.timezone import KST
+from bcsd_api.core.tables import app_settings
+from bcsd_api.core.timezone import KST
 
 from . import google as google_auth
 from . import token as jwt_token