docs: add PVE 8.4/9.0/9.1 research brief and ADR-008 version support matrix
Reviewed PVE 8.4, 9.0, and 9.1 release notes for storage subsystem changes
relevant to the plugin and Phase 3 design.
Key findings:
- iSCSI hostname portal support (PVE 8.4+) — gap in current plugin (#233)
- Snapshot-as-Volume-Chains (PVE 9.0 tech preview) — Phase 3 opportunity (#234)
- GlusterFS dropped in PVE 9 — confirms need for proper custom plugin
- pvemanagerlib.js still broken on PVE 8.4.x (#223, blocked)
ADR-008 records the PVE version support matrix:
- v2.x: PVE 7 (best-effort), PVE 8 (supported), PVE 9 (not supported)
- v3.0: PVE 8+ (core), PVE 9.0+ (snapshots)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
332b6a8257