M6 epic: VM/LXC associations and guest agent data

[Andreas-Froyland]

Tracking issue. Dependency and status checklists only — implementation stays in narrow linked issues.

Outcome

QEMU and LXC guests are discovered, normalized, and associated with Fleet machines, including guest-agent data with explicit unavailable states.

Supersedes

Replaces the guest inventory and machine-association parts of #3's manifest wiring.

Depends on

• M6 Proxmox accounts and discovery — merged, PR #100
• M2 machine, endpoint, and observation model — merged, commit 5daa677 (direct commit; no PR recorded)

Scope checklist

• QEMU/LXC discovery with per-resource failure isolation — FM-601 (FM-601 — Add Proxmox guest associations and guest-agent data #101, PR FM-601: Proxmox guest associations and guest-agent data #102)
• Stable association between a Proxmox guest and a Fleet machine identity — FM-601: evidence-only candidates (MAC > address > name), never silently merged; the confirmed claim records via observe-guest
• QEMU Guest Agent readiness and IP data, tolerant of loose or null API shapes — FM-601: per-surface availability (off = unavailable, LXC = unknown), loose-shape tolerance, loopback exclusion
• Explicit unavailable states rather than silently empty fields — FM-601: per-surface honest states, cluster-level warnings preserved in the snapshot

M6 acceptance (exit gate) — complete 2026-10-02

All PRs target the dev branch. Plan: docs/planning/m6-acceptance.md.

• FM-607 FM-607: Recorded PVE 8.x/9.x contract fixtures for discovery, guests, agent, and tasks #208 — recorded PVE 8.x/9.x contract fixtures (agent:codex) — merged, PR #241
• FM-608 FM-608: Windows guest health and IP via the QEMU Guest Agent #209 — Windows guest health/IP via QGA (agent:codex) — merged, PR #243

Constrained by

• docs/PLAN.md — M6; ADR-0005: provider DTOs translate at the boundary
• Version-specific API differences stay behind the provider

Non-goals

• Lifecycle actions (separate epics)
• Correlating guests into Fleet machines without displayed evidence