feat: make all hardcoded limits configurable via env vars

- bodyLimit: conditional on MAX_UPLOAD_SIZE_MB (0 = 1GB practical max)
- rate limiting: disabled when RATE_LIMIT_PER_MIN=0
- shutdown timeout: 8s → 30s
- upload plugin: no fileSize/files cap when env=0
- session duration: configurable via SESSION_DURATION_HOURS (default 168h)
- login attempts: configurable via LOGIN_ATTEMPT_LIMIT
- batch/pipeline/svg-to-raster: skip guard when MAX_BATCH_SIZE=0
- pipeline steps: configurable via MAX_PIPELINE_STEPS (0 = unlimited)
- user-files: remove 200 hard cap
- stitch canvas: configurable via MAX_CANVAS_PIXELS (0 = unlimited)
- PDF pages: configurable via MAX_PDF_PAGES (0 = unlimited)
- SVG size: configurable via MAX_SVG_SIZE_MB (0 = unlimited)
- logo size: configurable via MAX_LOGO_SIZE_KB (default 2048)
- worker threads: auto-detect via resolveWorkerThreads (0 = auto)
- megapixels: skip validation when MAX_MEGAPIXELS=0
- seam carving: remove 1200px dimension cap
- concurrency: auto-detect via resolveConcurrency (0 = auto)

apps/api/src/routes/tools/stitch.ts

@@ -4,14 +4,13 @@ import { basename, join } from "node:path";
 import type { FastifyInstance } from "fastify";
 import sharp from "sharp";
 import { z } from "zod";
+import { env } from "../../config.js";
 import { autoOrient } from "../../lib/auto-orient.js";
 import { formatZodErrors } from "../../lib/errors.js";
 import { validateImageBuffer } from "../../lib/file-validation.js";
 import { ensureSharpCompat } from "../../lib/heic-converter.js";
 import { createWorkspace } from "../../lib/workspace.js";
 
-const MAX_CANVAS_PIXELS = 100_000_000;
-
 const settingsSchema = z.object({
   direction: z.enum(["horizontal", "vertical", "grid"]).default("horizontal"),
   gridColumns: z.number().int().min(2).max(100).default(2),
@@ -180,9 +179,10 @@ export function registerStitch(app: FastifyInstance) {
         }
       }
 
-      if (canvasWidth * canvasHeight > MAX_CANVAS_PIXELS) {
+      const maxCanvasPixels = env.MAX_CANVAS_PIXELS > 0 ? env.MAX_CANVAS_PIXELS : Infinity;
+      if (canvasWidth * canvasHeight > maxCanvasPixels) {
         return reply.status(422).send({
-          error: `Canvas too large: ${canvasWidth}x${canvasHeight} (${Math.round((canvasWidth * canvasHeight) / 1_000_000)}MP exceeds 100MP limit)`,
+          error: `Canvas too large: ${canvasWidth}x${canvasHeight} (${Math.round((canvasWidth * canvasHeight) / 1_000_000)}MP exceeds ${Math.round(maxCanvasPixels / 1_000_000)}MP limit)`,
         });
       }