chore(web): upgrade Next.js to 16.3 preview

[hyoban]

Important

1. Make sure you have read our contribution guidelines
2. Ensure there is an associated issue and you have been assigned to it
3. Use the correct syntax to link this PR: Fixes #<issue number>.

Summary

Related issue: N/A

• Upgrade next, @next/mdx, and @next/eslint-plugin-next to the current preview channel version, 16.3.0-preview.5.
• Refresh the pnpm lockfile for the Next.js 16.3 preview package graph.
• Update affected frontend test router mocks for the new AppRouterInstance.bfcacheId field and keep the icon gallery Storybook glob typing compatible with the current type checker.

From Codex

Screenshots

Before	After
N/A	N/A

Checklist

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran make lint && make type-check (backend) and cd web && pnpm exec vp staged (frontend) to appease the lint gods

Validation

• pnpm --filter dify-web exec next --version
• pnpm --filter dify-web type-check
• pnpm -C web test 'app/(commonLayout)/app/(appDetailLayout)/[appId]/__tests__/layout-main.spec.tsx' 'app/(commonLayout)/datasets/(datasetDetailLayout)/[datasetId]/__tests__/layout-main.spec.tsx' 'app/components/header/account-dropdown/__tests__/index.spec.tsx'
• rm -rf web/.next && pnpm -C web build

[codecov]

Codecov Report

❌ Patch coverage is 76.92308% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.38%. Comparing base (46163c6) to head (b243c00).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
web/service/client.ts	76.92%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #38195      +/-   ##
==========================================
+ Coverage   85.32%   85.38%   +0.05%     
==========================================
  Files        4967     5122     +155     
  Lines      258521   262863    +4342     
  Branches    49059    50122    +1063     
==========================================
+ Hits       220595   224437    +3842     
- Misses      33633    34133     +500     
  Partials     4293     4293              

Flag	Coverage Δ
cli	88.45% <ø> (?)
dify-ui	94.93% <ø> (ø)
web	85.05% <76.92%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[hyoban]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Merged origin/main and resolved the two conflicts (commit b995846):

• web/service/client.ts: kept main's createConsoleDynamicLink<ConsoleClientContext>(createConsoleOpenAPILink) — this factory already calls logClientError internally via the onError interceptor inside createConsoleOpenAPILink, so the abort-error suppression from this PR is preserved.
• web/service/client.spec.ts: retained both test suites as separate describe blocks — logClientError (abort-error suppression, from this PR) and consoleQuery transport context (silent-context and repeated-query-param serialisation, from main). All 23 tests pass.