Restructure TOC by audience (Phase 1: navigation)

[RDMacLachlan]

Summary

Restructures msix-src/toc.yml into seven audience-oriented top-level nodes to optimize navigation for the three target audiences (Development, App repackaging, App Deployment):

1. Overview and concepts — what MSIX is, containerization, supported platforms, appContainer, flexible virtualization, App-V vs MSIX, package formats
2. Develop MSIX apps (Development) — from-source, VS packaging, command line, signing, CI/CD, extend, update from code, MSIX SDK
3. Repackage existing apps (App repackaging) — Packaging Tool setup/use, PSF, post-package tasks, MSIX Toolkit
4. Deploy and manage MSIX (App Deployment) — deployment planning, App Installer, enterprise/web/consumer distribution, updates, shared package container, MSIX Core
5. Reference — APIs and schemas
6. Troubleshooting and validation
7. Resources — MSIX resources, partners, customer journeys

Scope & safety

• Navigation-only change. No article files are moved or renamed; no published URLs change; no redirects required.
• Every article href is preserved — verified programmatically that all 167 distinct hrefs from the previous TOC remain reachable (0 dropped, 0 added). displayName search hints and external ?context=/windows/msix/render links are retained.
• This is Phase 1 of the docs restructure. Content right-sizing (splitting long articles into 3–4 minute reads and adding how-to + sample coverage per feature) will follow in separate, bounded PRs.

[learn-build-service-prod]

Learn Build status updates of commit 648831a:

✅ Validation status: passed

File	Status	Preview URL	Details
msix-src/toc.yml	✅Succeeded

For more details, please refer to the build report.