test: add a local Docker test environment for all features

testenv/ starts two real NetBox 4.7 instances (v2 and v1 token), SSH
targets on public, mgmt, and prod networks, a jump host, an IPv6-only
host, a static host, and a client with ssh, sftp, scp, tmux, zellij,
bash, zsh, and fish. A seed script fills NetBox through the REST API.

141 end-to-end checks cover cache and refresh filters, connecting,
all resolver strategies, multiple instances, shortcuts and rewrites,
SSH options and rules, static hosts, sftp/scp incl. IPv6 and jump
hosts, tunnels, local notes and NetBox comments, completion and shell
hooks, the TUI (driven through tmux), the configurator, and uninstall.

Local only: testenv/up.sh, test.sh, shell.sh, down.sh. Not part of
CI/CD.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

testenv/tests/07-static.sh

@@ -0,0 +1,25 @@
+# Static hosts without any NetBox: config, CLI, own user/port/options, rules.
+config_only <<'EOF'
+ssh:
+  default_user: ops
+  rules:
+    - match: {kind: static, tag: legacy}
+      options: {ServerAliveInterval: "15"}
+hosts:
+  - name: legacy-box
+    address: 10.231.0.50
+    user: admin
+    tags: [legacy]
+EOF
+expect_eq "connect to a static host" "legacy-box" netssh legacy-box hostname
+expect_eq "static user" "admin" netssh legacy-box whoami
+expect_out "rule by kind and tag" "-o serveraliveinterval=15" netssh --dry-run legacy-box
+expect_eq "-l still wins" "ops" netssh -l ops legacy-box whoami
+check "hosts add" netssh hosts add box2 10.231.0.50 --port 2222 --tag lab
+expect_eq "hosts list" "box2 10.231.0.50 2222 lab" bash -c 'netssh hosts list | grep "^box2" | tr -s " "' 
+expect_out "static port" " 2222" netssh box2 'echo $SSH_CONNECTION'
+expect_out "completion" "box2" netssh __complete bo
+expect_fail "duplicate" "already exists" netssh hosts add box2 10.0.0.1
+check "hosts remove" netssh hosts remove box2
+expect_fail "removed host is gone" "no NetBox is configured" netssh --dry-run box2
+expect_eq "sftp to a static host" "Remote working directory: /home/admin" bash -c 'echo pwd | netssh sftp -b - legacy-box | grep Remote'