Oikos Week 1: kernel policy, ontology, service contract, topology gen

Adds the Oikos agent-OS kernel: oikos/policy.yaml (risk classes +
approval rules for every homelab/MCP command), oikos/ontology.yaml
(8-domain systems model, typed relationships, node lifecycle), and
OIKOS.md (OODA loop operating brief, linked from AGENTS.md).

Extends inventory.yaml with a stable service contract (doc_page,
config_repo, risk_notes) on all 17 services, and a structured
archaeology: section for the 13 destroyed LXCs (was scattered
comments + a narrative table). Fixes stale drift found in the
process: authentik's backend pointed at a retired LXC (124); core
has run on the VPS since 2026-05-31.

Adds oikos/gen-topology.py, generating infrastructure/topology.md
(Mermaid compute/ingress + storage views) from inventory.yaml.
build_host_files.py now carries state/storage/depends_on into
generated hosts/*.yaml.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

OIKOS.md

@@ -0,0 +1,107 @@
+# Oikos — the operating model
+
+Oikos (Greek: *household*) is the agent operating system layered on this
+repo. It is not new infrastructure: `inventory.yaml` is the kernel data
+structure, the `homelab` CLI and MCP server are the syscall surface, and
+this page defines the rules everything above them follows.
+
+Read this after [AGENTS.md](AGENTS.md). Machine-readable companions:
+[oikos/ontology.yaml](oikos/ontology.yaml) (systems model),
+[oikos/policy.yaml](oikos/policy.yaml) (risk & approval).
+
+## The kernel loop: OODA
+
+Every Oikos activity — scheduled probe, agent task, operator request — is
+one pass through **Observe → Orient → Decide → Act**:
+
+1. **Observe** — probes, drift detectors, and agent findings produce
+   **Signals** (structured records, not loose messages): pending updates,
+   high temperature, low disk, service down, cert expiry, stale backup,
+   inventory drift.
+2. **Orient** — walk the ontology graph: what entity is affected, what
+   depends on it (blast radius), its lifecycle state, whether a runbook
+   matches, what the ledger says about past attempts.
+3. **Decide** — the classifier scores **risk class × blast radius ×
+   confidence** and routes:
+   - **auto-act**: within autonomy policy, high confidence, contained radius
+   - **escalate**: operator approval via Matrix (✅/❌ reaction; destructive
+     actions additionally need a typed confirmation phrase)
+   - **queue**: informational — console + reports
+   The classifier can only *lower* autonomy relative to policy, never raise
+   it. When in doubt, escalate.
+4. **Act** — execute through `homelab` commands or runbooks (never ad-hoc
+   SSH), then **verify** with the action's verification command, write a
+   **ledger** entry, resolve the Signal, and update docs in the same session.
+
+## Primitives
+
+| Primitive | What it is | Lives in |
+|---|---|---|
+| Host / Service | topology entities | `inventory.yaml` (+ generated `hosts/*.yaml`) |
+| Secret | SOPS+age encrypted value, per-client recipients | `secrets/` + `.sops.yaml` |
+| Runbook | executable workflow with risk class + verification | `runbooks/` (Week 2) |
+| Signal | something needing attention, with lifecycle | `signals/` ledger (Week 3) |
+| Change | one mutation: who, what, risk, approval, verification | `ledger/` (Week 2) |
+| Approval | short-TTL signed grant for a gated action | approval engine (Week 3) |
+| Incident | investigation narrative | `investigations/` |
+| Plan | design doc for non-trivial work | `plans/` |
+| Agent | enrolled client identity = its age pubkey | `inventory.yaml` + `.sops.yaml` |
+
+## Risk classes (enforced, not advisory)
+
+From [oikos/policy.yaml](oikos/policy.yaml):
+
+- **read_only** — status, logs, docs, inventory. Unattended.
+- **reversible_low** — restart, cache clear, sync pull. Unattended + ledger.
+- **config_mutation** — tracked-config edits (commit+push, never local),
+  deploys, upgrades, DNS/ingress changes. Operator approval.
+- **destructive** — destroy, format, wipe, rotate, revoke. Approval +
+  typed confirmation phrase.
+
+Lifecycle gates modify these: `provisioning` nodes are freely mutable
+(nothing depends on them); `deprecated` nodes accept no new dependents;
+anything touching a `destroyed` node is drift.
+
+## The systems model
+
+Eight domains — physical, compute, network, storage, software,
+identity & access, operations, external — cover everything in the lab;
+entities are connected by typed edges (`hosts`, `provides`, `mounts`,
+`stores-on`, `routes-to`, `can-decrypt`, `depends-on`, `backs-up-to`, …)
+defined in [oikos/ontology.yaml](oikos/ontology.yaml). Rule of
+completeness: **if it can break, be changed, or hold data, it has an
+entity and edges.** Blast-radius questions ("what breaks if strong goes
+down?") are graph walks, not doc archaeology.
+
+Nodes move through an explicit lifecycle —
+`planned → provisioning → active → migrating → deprecated → destroyed` —
+stored as `state:` in inventory (absent = active). Destroyed nodes live in
+the `archaeology:` section. Each transition is a runbook checklist;
+deprecation completes only when inbound edges reach zero.
+
+Generated views: [infrastructure/topology.md](infrastructure/topology.md)
+(Mermaid, regenerated from inventory).
+
+## Conventions carried forward
+
+- Inventory is the truth; live state wins over narrative docs.
+- Prefer `homelab` CLI and MCP over ad-hoc SSH.
+- Meaningful changes update docs in the same session.
+- Secrets are decrypted locally via per-client keys; never into docs/comments.
+- Tracked configs change by commit + push, not local edits.
+- Netbird is the preferred mesh path for new traffic.
+- Agents are terse ([CAVEMAN.md](CAVEMAN.md)), verify claims, and fix
+  collateral drift when found.
+
+## Build status (30-day roadmap, started 2026-07-05)
+
+- **Week 1 (this)**: policy, ontology, service contract, archaeology,
+  topology generator, this brief.
+- **Week 2**: context cards, `homelab service <name> …`, change ledger,
+  `node relations`, runbooks.
+- **Week 3**: Prometheus + node_exporter, ops scheduler + state cache,
+  drift detectors, signal engine, decision classifier, approval engine
+  (Matrix ✅/❌), daily brief.
+- **Week 4**: Oikos Console (oikos.hubris.network, behind Authentik with
+  step-up re-auth on approvals), per-agent age-key-signed approval
+  requests, docs pass, 60/90-day backlog.