docs: Add Accore distribution architecture ADRs

[Emran025]

Summary

Adds the proposed architecture decisions and operational policy required to start the self-contained Accore Server and trusted Accore Client distribution programme.

Included

• ADR-004: Server/Client product flavours and Windows x64 reference target.
• ADR-005: Private AccoreDB runtime, persistent-data boundary, and recovery policy.
• ADR-006: Client/Server TLS trust, pairing, enrolment, and network boundary.
• ADR-007: Release signing, Server Agent lifecycle authority, and update recovery.
• Accore Server Lifecycle and Recovery Policy.
• Indexed English distribution plan and linked GitHub issue hierarchy.

Validation

• All ADRs contain context, decision, alternatives, and approval record.
• Staged documentation passes git diff --check.
• Documentation index links were updated.

Review requested

Please approve the outstanding platform, database licensing, TLS, signing-key custody, backup, and recovery policy decisions before implementation issues #40 onward are marked complete.

Refs #39

[Emran025]

Technical review update:

PR #55 is documentation-only and does not modify frontend localisation or test code. It has been rebased onto current main. Its quality gate is presently blocked by the same repository-level i18n inventory state: 28198 candidates, 1 pending review.

The prior setup-route quote assertion mismatch has been isolated in PR #56. This documentation PR remains blocked from merge until the required quality and backend gates pass; it will not be merged by bypassing CI.