ci: relax file-size ceilings by surface (#6485)

## Summary

- raise Desktop Rust's differential file-size ceiling from 1,000 to
1,500 lines
- raise Desktop frontend and Mobile ceilings from 1,000 to 1,200 lines
- keep Web at 1,000 lines and preserve the existing no-growth ratchet
above each ceiling

## Why

The flat 1,000-line limit is forcing mechanical trimming in Desktop and
Mobile even for small cohesive changes. Surface-specific ceilings
relieve that pressure without granting Web or every authored component a
blanket 2,000-line budget.

## Testing

- `just file-size-check`
- `cd desktop && pnpm exec biome check scripts/check-file-sizes.mjs`
- `node --check mobile/scripts/check-file-sizes.mjs`
- `git diff HEAD^ --check`

Signed-off-by: Wes <wesbillman@users.noreply.github.com>
Co-authored-by: Carl <32a2e2c9d428ee08902cab75d956da2c1d235a22d4766b0dd4138bf6e2e5db1d@buzz.block.builderlab.xyz>

web/scripts/check-file-sizes.mjs

@@ -1,32 +1,21 @@
+import { realpathSync } from "node:fs";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
 import { runFileSizeCheck } from "../../scripts/check-file-sizes-core.mjs";
+import { rules } from "./file-size-policy.mjs";
 
-const __dirname = path.dirname(fileURLToPath(import.meta.url));
-const projectRoot = path.resolve(__dirname, "..");
+const scriptPath = realpathSync(fileURLToPath(import.meta.url));
+const projectRoot = path.resolve(path.dirname(scriptPath), "..");
 
-const MAX_LINES = 1000;
-
-const rules = [
-  {
-    root: "src/app",
-    extensions: new Set([".ts", ".tsx"]),
-    maxLines: MAX_LINES,
-  },
-  {
-    root: "src/features",
-    extensions: new Set([".ts", ".tsx"]),
-    maxLines: MAX_LINES,
-  },
-  {
-    root: "src/shared/api",
-    extensions: new Set([".ts", ".tsx"]),
-    maxLines: MAX_LINES,
-  },
-];
-
-await runFileSizeCheck({
+export const policy = {
   projectRoot,
   rules,
   label: "Web",
-});
+};
+
+if (
+  process.argv[1] &&
+  realpathSync(path.resolve(process.argv[1])) === scriptPath
+) {
+  await runFileSizeCheck(policy);
+}

web/scripts/file-size-policy.mjs

@@ -0,0 +1,19 @@
+const MAX_LINES = 1000;
+
+export const rules = [
+  {
+    root: "src/app",
+    extensions: new Set([".ts", ".tsx"]),
+    maxLines: MAX_LINES,
+  },
+  {
+    root: "src/features",
+    extensions: new Set([".ts", ".tsx"]),
+    maxLines: MAX_LINES,
+  },
+  {
+    root: "src/shared/api",
+    extensions: new Set([".ts", ".tsx"]),
+    maxLines: MAX_LINES,
+  },
+];