feat: add ChirpStack Cloudron package (Infrastructure) [#668]

ChirpStack 4.19.1 (LoRaWAN network server) as the 14th package:
official-image wrapper, digest-pinned, with only bash added to the
upstream alpine runtime. Native OIDC login wired to the Cloudron
platform provider (openid_connect backend, config regenerated every
start); postgresql + redis addons; diesel migrations auto-run.
Operator config (NetID, US915 region, gateway MQTT backend) lives in
seeded files under /app/data/config. Build green; config generation
validated through chirpstack's own TOML parser. Docs gardened to 14
packages.

Ticket: https://projects.knownelement.com/issues/668

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Package-Workspace/Infrastructure/chirpstack/.env.example

@@ -0,0 +1,13 @@
+# ChirpStack Cloudron package - optional env knobs
+# (set via `cloudron env set`, restart to apply)
+#
+# Authentication backend. Default: openid_connect (Cloudron SSO).
+# Use "internal" ONLY for the one-time admin bootstrap described in
+# README.md, then switch back.
+CHIRPSTACK_AUTH_MODE=openid_connect
+
+# Auto-register users on first SSO login (true/false).
+CHIRPSTACK_OIDC_REGISTRATION=true
+
+# Log level: trace | debug | info | warn | error.
+CHIRPSTACK_LOG_LEVEL=info