feat(inventory): bring nh3-dev under infra-ops management

Adds the NH3 dev box (10.100.10.50) as a managed host: README, first
system-details snapshot, ssh-target. Adds it to the fleet bootstrap's
Tier 1 and the CLAUDE.md servers table. infra-ops identity bootstrapped
there (operator-run) — NOPASSWD sudo + key, so root-level infra work on
the box (it runs the egress proxy, ttyd seat, mead-hall, volva, and dev
checkouts) no longer needs a per-task password.

First use: installed Playwright headless-Chromium system deps + binary
for bloom_music's OSMD browser-geometry test harness; headless launch +
real SVG geometry verified.

servers/nh3-dev/README.md

@@ -0,0 +1,37 @@
+# nh3-dev
+
+NH3-site **developer box** — `10.100.10.50` (WireGuard-reachable from the NH3
+subnet). General-purpose dev VM that hosts agent-fleet sidecars and live Claude
+Code sessions; **not** a Docker-stack host in the `stacks/` sense.
+
+**Reach:** `ssh 10.100.10.50` (as `lkraven`), or the dedicated agent identity
+`ssh -i ~/.ssh/infra-ops_ed25519 infra-ops@10.100.10.50` (NOPASSWD sudo).
+`infra-ops` bootstrapped here 2026-06-04 (see [`reference_infra_ops_sudo_identity`]
+in auto-memory). Note: Claude Code sessions often run **natively on this box**, so
+local Bash already executes here — no SSH-to-self needed for non-privileged work.
+
+## What runs here
+
+- **NH3 egress proxy** — durable internal-only SOCKS5 `socks5h://10.100.10.50:1080`
+  (dante, ACL'd to the WG net). Residential egress for colo services gated on their
+  datacenter IP (e.g. YouTube bot-gate). Runbook + setup committed; consumers point
+  `*_PROXY` at it.
+- **ttyd fleet driver-seat** — web/iPad seat into the zellij `Claude` session (ttyd
+  behind Caddy; OSC52 clipboard shim). User systemd services under `~/.config`.
+- **mead-hall** — Bifrost tool-provider sidecar (`:5173`), CI-deployed from
+  `vh/mead-hall`.
+- **volva** — Codex peer agent on the althing bus (single-turn oracle, systemd
+  daemon).
+- **bloom_music dev** — `~/development/bloom_music`; its `web/` test harness uses
+  Playwright headless Chromium. System deps + the managed Chromium binary
+  (`~/.cache/ms-playwright`) installed 2026-06-04 via `infra-ops`; headless launch +
+  real SVG geometry verified.
+
+## Notes
+
+- **PFI-owned Linux** — in scope for `infra-ops` management (apt, systemctl, service
+  lifecycle). Added to the fleet bootstrap's Tier 1.
+- OS: Debian 12 (bookworm). See `system-details.txt` for the latest snapshot
+  (`scripts/refresh-server-info.sh nh3-dev`).
+- Not in the colo Docker-stack topology — no `/opt/docker/compose` deploy target;
+  workloads are systemd services + dev checkouts.