docs: streamline & consolidate the tree (phase 6)

Problem: after the wiki-hq reorg, agent-instruction and human-doc domains
were still scattered across the repo root, with three now-redundant stub
files cluttering it. The organizing principle wasn't visible in the layout.

Change — enforce three clear buckets:
- .agents/  = how agents operate: OIKOS.md, HERMES.md (moved from root),
  shared/ conventions, domains/ schemas, skills/, and operations/ (operator
  cheatsheet + enrollment + hermes-agent, moved from root).
- knowledge/ = what exists + evidence: wiki/, GLOSSARY.md, and sources/ now
  including investigations/ (incident records are evidence/sources).
- root = substrate + two entry points (AGENTS.md, README.md), plus plans/
  as its own design-intent domain.

Moves:
- investigations/ -> knowledge/sources/investigations/ (incl. archive/, index).
- operations/ -> .agents/operations/.
- HERMES.md -> .agents/HERMES.md.
- Deleted unreferenced root stubs CAVEMAN.md, CONTRIBUTING.md, and OIKOS.md
  (its 7 remaining linkers repointed to .agents/OIKOS.md).

Consumers updated:
- inventory.yaml doc_page (agent-enrollment) + regenerated hosts/*.yaml + cards.
- tools/setup-hermes-soul.sh and bootstrap.sh (x2) -> .agents/HERMES.md.
- bin/homelab help string -> .agents/operations/hermes-agent.md.
- knowledge/operations schemas, llm-wiki, page-templates, incident-investigation
  skill, AGENTS.md/README nav -> new investigations/operations paths.
- All markdown links rewritten via the path-resolving mapper.

Left in place (substrate/executable/separate-domain): hosts/, ledger/, tools/,
plans/, oikos/, mcp/, secrets/, bin/, inventory.yaml.

Verification: docs-lint at baseline (2 intentional cross-repo refs, no new
breakage); gen-topology.py --check exit 0; build_host_files.py idempotent; all
doc_page targets resolve; Hermes provisioning scripts point at the new path.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.agents/HERMES.md

@@ -0,0 +1,96 @@
+# HERMES.md — Agent persona for homelab clients
+
+This file is the canonical agent persona for **all** AI agents running on
+machines in the **hubris** homelab. It prescribes behaviour, token-efficiency
+conventions, and the source-of-truth hierarchy.
+
+## Source of truth
+
+The homelab-context repo at `/opt/homelab-context/` is the single source of
+truth for:
+- Fleet topology (`inventory.yaml`, `hosts/*.yaml`)
+- Service endpoints and credentials (via `homelab secret`)
+- Agent behaviour and conventions
+- Everything in this file
+
+When in doubt, check `/opt/homelab-context/` first.
+
+## Runbooks — load, don't rediscover
+
+For the canonical workflows (service health check, config change +
+deploy, client enrollment, incident investigation, and each node
+lifecycle transition), read the matching `.agents/skills/<name>/SKILL.md` before
+acting. Each skill carries its risk class, required inputs, the
+verification command, and a docs-update checklist in its frontmatter —
+classify against `oikos/policy.yaml` using that risk class before any
+mutation. Don't re-derive topology or the mutation path by grepping the
+wiki when a runbook already encodes it. See [OIKOS.md](OIKOS.md) for the
+operating model these runbooks execute inside (OODA loop, risk classes,
+approval flow, ontology).
+
+## Agent type — how this file gets loaded
+
+| Agent | Loading mechanism |
+|-------|------------------|
+| **Hermes** | `tools/setup-hermes-soul.sh` (auto-setup) → provisions `~/.hermes/SOUL.md` from this file |
+| **Goose** | `.goosehints` symlink at `~/.config/goose/.goosehints` → `/opt/homelab-context/HERMES.md` |
+| **Claude Code / Codex** | Symlink or copy this file into the project's `CLAUDES.md` / `.claude` instructions |
+
+**Do not edit SOUL.md or .goosehints directly.** Edit this file in the
+homelab-context repo instead. Changes propagate to all clients on the next
+sync (`sudo homelab sync`).
+
+---
+
+## Token efficiency (caveman skill)
+
+All homelab agents use the **Caveman + RTK** token optimization approach from
+https://github.com/adityahimaone/hermes-agent-rtk-caveman.
+
+### Before running any CLI command, ask:
+
+1. **Is there a caveman wrapper equivalent?** Use the wrapper for token-efficient
+   output. Available wrappers (installed at `~/bin/caveman_wrapper.sh`):
+   - `~/bin/caveman_wrapper.sh git-status` — compact git status
+   - `~/bin/caveman_wrapper.sh git-log [n]` — compact git log
+   - `~/bin/caveman_wrapper.sh lint [target]` — compact lint results
+   - `~/bin/caveman_wrapper.sh test-results [cmd]` — compact test results
+
+2. **If no caveman wrapper exists, pipe through `rtk`** to compress output:
+   ```
+   rtk <command>
+   ```
+   RTK (Rust Token Killer) strips redundant whitespace, trims long paths, and
+   deduplicates repeated lines. This reduces token usage by 60-90% on CLI
+   operations.
+
+3. **For homelab operations**, prefer the `homelab` CLI or MCP tools over
+   raw SSH/shell — they're already token-optimized.
+
+### Templates
+
+Caveman templates live at `~/templates/`:
+- `git_status.txt` — compact git status format
+- `git_log.txt` — compact git log format
+- `lint_results.txt` — compact ESLint format
+- `test_results.txt` — compact vitest/jest format
+
+### When to skip caveman/rtk
+
+- Interactive commands (editors, prompts) — let human-readable output pass
+- Commands with no output — skip entirely
+- When you need the exact raw output for post-processing
+
+### Verification
+
+```bash
+ls ~/bin/caveman_wrapper.sh && echo "caveman ready"
+```
+
+## Important note for Hermes agents
+
+If you are reading this as a Hermes agent, your SOUL.md was auto-provisioned
+by `tools/setup-hermes-soul.sh`. This file is the canonical original — you
+can verify the content matches or re-provision by running:
+
+    bash /opt/homelab-context/tools/setup-hermes-soul.sh