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/05-shortcuts.sh

@@ -0,0 +1,31 @@
+# Domains, hyphen folding, rewrite rules, alias --test, completion, aliases.
+config <<'EOF'
+resolver:
+  strategies: [management_subnet, primary_ip]
+  management_subnets: [10.231.1.0/24]
+ssh: {default_user: ops}
+shortcuts:
+  domains: [.hoster.test]
+  rewrites:
+    - pattern: '^([a-z]+)[0-9]+-'
+      replace: '$1'
+EOF
+check "refresh" netssh cache refresh
+expect_eq "domain expansion via NetBox" "fsn1-pve1" netssh fsn/fsn1-pve1 hostname
+expect_eq "rewrite shortcut, qualified" "fsn1-pve2" netssh fsn/fsnpve2 hostname
+expect_eq "rewrite shortcut, unqualified" "fsn1-pve3" netssh fsnpve3 hostname
+expect_out "alias --test" "fsn1-pve1.hoster.test → fsnpve1" netssh alias --test fsn1-pve1.hoster.test
+expect_out "completion offers shortcuts" "fsnpve1" netssh __complete fsnp
+expect_out "aliases use the shortcut" "alias fsn_fsnpve1='netssh " netssh alias --shell bash
+expect_fail "unknown shortcut" "host not found" netssh --dry-run fsnpve9
+
+config <<'EOF'
+resolver:
+  strategies: [management_subnet, primary_ip]
+  management_subnets: [10.231.1.0/24]
+shortcuts:
+  domains: [.hoster.test]
+  strip_hyphens: true
+EOF
+check "refresh" netssh cache refresh
+expect_eq "hyphen folding" "ssh 10.231.1.12" netssh --dry-run fsn/fsn1pve2