Add 17 features: My Work view, card copy/numbering, calendar, bulk ops, custom fields, automations, webhooks, invites, import/export, and more

Features implemented across 6 batches:
- Batch A: Fix ColorPicker gradient sync, tenant custom logo, unarchive cards, board backgrounds
- Batch B: My Work view, card copy/duplicate, card numbering (BOARD-123)
- Batch C: Due date reminders (cron), card watching with notifications
- Batch D: Bulk card operations, column sorting, calendar view
- Batch E: Invite by link, board import/export (Pounce + Trello JSON)
- Batch F: Webhooks with HMAC signing, custom fields, automation rules engine

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/routes/api/boards/[boardId]/custom-fields/[fieldId]/+server.ts

@@ -0,0 +1,50 @@
+import { json, error } from '@sveltejs/kit';
+import type { RequestHandler } from './$types.js';
+import { withTenant } from '$lib/server/rls.js';
+import { requireBoardEditor } from '$lib/server/guards.js';
+
+export const PATCH: RequestHandler = async ({ params, request, locals }) => {
+	const tenant = locals.tenant;
+	if (!tenant) throw error(400, 'Unknown tenant');
+
+	const body = await request.json();
+
+	const field = await withTenant(tenant.id, async (tx) => {
+		await requireBoardEditor(tx, locals.user, params.boardId, tenant.id);
+
+		const existing = await tx.customFieldDef.findFirst({
+			where: { id: params.fieldId, boardId: params.boardId }
+		});
+		if (!existing) throw error(404, 'Field not found');
+
+		const data: Record<string, any> = {};
+		if (body.name !== undefined) data.name = body.name;
+		if (body.options !== undefined) data.options = body.options;
+		if (body.position !== undefined) data.position = body.position;
+
+		return tx.customFieldDef.update({
+			where: { id: params.fieldId },
+			data
+		});
+	});
+
+	return json({ field });
+};
+
+export const DELETE: RequestHandler = async ({ params, locals }) => {
+	const tenant = locals.tenant;
+	if (!tenant) throw error(400, 'Unknown tenant');
+
+	await withTenant(tenant.id, async (tx) => {
+		await requireBoardEditor(tx, locals.user, params.boardId, tenant.id);
+
+		const existing = await tx.customFieldDef.findFirst({
+			where: { id: params.fieldId, boardId: params.boardId }
+		});
+		if (!existing) throw error(404, 'Field not found');
+
+		await tx.customFieldDef.delete({ where: { id: params.fieldId } });
+	});
+
+	return json({ ok: true });
+};