fix(desktop): fit review files and comments to the bridge envelope

Per-field limits did not guarantee the aggregate review fit the shell's
byte envelope; the projection now admits files and the newest comments by
remaining bytes and flags truncation.

Claude-Session: https://claude.ai/code/session_01JNnE9qzUZMMnqpZWCqM3nb

src/main/runtime/rpc/methods/mobile-web-review-projection.ts

@@ -1,3 +1,4 @@
+import { MOBILE_WEB_BRIDGE_MAX_OPERATION_BYTES } from '../../../../shared/mobile-web/bridge-limits'
 import type { PRCheckDetail } from '../../../../shared/github/check-types'
 import type {
   GitHubAssignableUser,
@@ -57,7 +58,7 @@ export function projectMobileWebReview(
   const comments = projectMobileWebReviewComments(details.provider, details.item.comments)
   const files = projectMobileWebReviewFiles(details)
   const participants = details.provider === 'github' ? details.item.item : null
-  return MobileWebProviderReviewSchema.parse({
+  const review = MobileWebProviderReviewSchema.parse({
     ...base,
     ...(headSha ? { headSha } : {}),
     body: details.item.body.slice(0, MOBILE_WEB_PROVIDER_REVIEW_BODY_MAX_CHARACTERS),
@@ -73,6 +74,30 @@ export function projectMobileWebReview(
     canComment: true,
     allowedSubmissionActions: submissionActions(summary, headSha)
   })
+  review.comments = []
+  review.files = []
+  // Reserve room for the response identity; JSON escaping counts toward the shell's byte envelope.
+  let remaining =
+    MOBILE_WEB_BRIDGE_MAX_OPERATION_BYTES - 8192 - Buffer.byteLength(JSON.stringify(review))
+  for (const file of files.items) {
+    const bytes = Buffer.byteLength(JSON.stringify(file)) + 1
+    if (bytes > remaining) {
+      break
+    }
+    remaining -= bytes
+    review.files.push(file)
+  }
+  for (const comment of comments.items.toReversed()) {
+    const bytes = Buffer.byteLength(JSON.stringify(comment)) + 1
+    if (bytes > remaining) {
+      break
+    }
+    remaining -= bytes
+    review.comments.unshift(comment)
+  }
+  review.filesTruncated ||= review.files.length < files.items.length
+  review.commentsTruncated ||= review.comments.length < comments.items.length
+  return review
 }
 
 /** A review only accepts a verdict while it is still open, and only against a known head. */

src/main/runtime/rpc/methods/mobile-web-review-reads.test.ts

@@ -1,4 +1,6 @@
 import { describe, expect, it } from 'vitest'
+import { MOBILE_WEB_BRIDGE_MAX_OPERATION_BYTES } from '../../../../shared/mobile-web/bridge-limits'
+import type { MobileWebProviderReview } from '../../../../shared/mobile-web/provider-review-contract'
 import {
   gitHubReviewDetails,
   gitLabReviewDetails,
@@ -108,6 +110,72 @@ describe('host-projected provider review reads', () => {
     })
   })
 
+  it.each([
+    ['github', false],
+    ['gitlab', false],
+    ['github', true]
+  ] as const)(
+    'fits escaped %s review content with crowded checks=%s in the shell envelope',
+    async (provider, crowded) => {
+      const comments = Array.from({ length: 32 }, (_, id) => ({
+        id,
+        author: 'a'.repeat(160),
+        authorAvatarUrl: '',
+        url: '',
+        body: '\u0000'.repeat(4096),
+        createdAt: '2026-09-07'
+      }))
+      const details = {
+        body: '\u0000'.repeat(32 * 1024),
+        comments,
+        files: Array.from({ length: 48 }, (_, index) => ({
+          path: `${index}${'界'.repeat(1000)}`,
+          ...(crowded ? { oldPath: `${index}${'旧'.repeat(1000)}` } : {}),
+          status: 'modified' as const,
+          additions: 0,
+          deletions: 0,
+          isBinary: false
+        }))
+      }
+      const f = reviewRuntime({
+        getRuntimeGitStatus: reviewStatus(),
+        getHostedReviewForBranch: hostedReviewSummary({ provider }),
+        ...(provider === 'github'
+          ? {
+              getRepoWorkItemDetails: gitHubReviewDetails({
+                ...details,
+                checks: crowded
+                  ? Array.from({ length: 128 }, () => ({
+                      name: '\u0000'.repeat(256),
+                      status: 'completed' as const,
+                      conclusion: 'success' as const,
+                      url: null
+                    }))
+                  : []
+              })
+            }
+          : { getGitLabRepoWorkItemDetails: gitLabReviewDetails(details) })
+      })
+      const result = (await runReviewMethod(
+        'mobileWeb.review.read',
+        REVIEW_IDENTITY,
+        f.context
+      )) as { review: MobileWebProviderReview }
+      expect(Buffer.byteLength(JSON.stringify(result))).toBeLessThan(
+        MOBILE_WEB_BRIDGE_MAX_OPERATION_BYTES
+      )
+      expect(result.review.commentsTruncated).toBe(true)
+      if (!crowded) {
+        expect(result.review.comments.length).toBeGreaterThan(0)
+        expect(result.review.comments.at(-1)?.id).toBe('31')
+        expect(result.review.files).toHaveLength(48)
+      } else {
+        expect(result.review.filesTruncated).toBe(true)
+        expect(result.review.files.length).toBeLessThan(48)
+      }
+    }
+  )
+
   it('refuses a read composed against a head the repository has moved off', async () => {
     const f = reviewRuntime({ getRuntimeGitStatus: reviewStatus({ head: 'c'.repeat(40) }) })