Milestone D.2.8 — NotFound + home redirect

Status: Complete
Goal: D.2
Phase: 1.5 — Docs Site
Wave: 2
Estimated effort: 1 hour
ADR required: None

Spec detail: MASTER_BRIEF.md Part D (D.2.8).

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Why This Milestone Exists

Broken links and mistyped URLs must return HTTP 404 with branded recovery paths, not a generic Next.js error or soft 200.

Landing site visitors following old links need clear paths back to ibexharness.com and docs home.

D.5.2 verify_phase15.sh asserts 404 status — this page must exist before launch verification.

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Non-Goals

• Custom error boundary for 500 errors
• Redirect map for renamed URLs (post-launch ops)
• Search on 404 page

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Branch

feat/d2-8-not-found

PR Title

feat(docs): styled 404 and home redirect (D.2.8)

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Prerequisites

• D.2.1 merged
• D.2.7 merged

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Deliverables

• docs/app/src/app/not-found.tsx — 72px mono 404, outline buttons
• Buttons: "Back to home" → https://ibexharness.com, "Documentation home" → introduction
• Confirm / → /docs/getting-started/introduction redirect from D.2.1

See MASTER_BRIEF Part D (D.2.8) for full acceptance detail.

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Files Affected

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Testing Requirements

• verifyNotFound_Http404: curl -I /this-page-does-not-exist returns status 404
• verifyNotFound_LandingLink: Page contains link to ibexharness.com
• verifyRootRedirect_Introduction: / redirects to introduction

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Acceptance Criteria

• Visiting unknown path returns styled 404 with HTTP 404
• Two recovery buttons render and navigate correctly
• Root redirect to introduction still works

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Risks