Fix zone list filtering and BIND warning display; add a views guide

- jarl zone list showed only primary zones. zone create binds its --type
  flag (default "primary") to the same variable as list's --type, so the
  default leaked into the list filter and hid hint, secondary and forward
  zones. list now has its own variable. TestListQueries runs list
  commands against a fake server and checks the filters they send.
- named-checkconf/named-checkzone messages are classified by the tool's
  exit code: on success, everything printed is a warning. Warnings such
  as 'both "recursion no;" and "allow-recursion" active' were shown as
  errors. The CLI, jarld check and the web UI now label them as warnings
  and skip the routine "loaded serial" lines.
- The zone_outside_view error points at --adopt-zones.
- docs/views.md: step-by-step split DNS for a server that has no views
  yet, tested on a copy of a stock Ubuntu 26.04 setup. Linked from the
  README, concepts and validation docs.

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

CHANGELOG.md

@@ -18,8 +18,16 @@ The first version, to be released as 0.1.0.
 - Problems printed by `jarld check` show zone names without the trailing dot.
 - `jarl` now shows the warnings a change introduces when it is applied or
   staged, not only on dry runs.
-- `jarl check` and `jarl resync` print only named-checkconf errors, not its
-  "loaded serial" lines.
+- `jarl check` and `jarl resync` no longer print named-checkconf's routine
+  "loaded serial" lines, only its errors and warnings.
+- `jarl zone list` showed only primary zones: `zone create`'s default
+  `--type primary` leaked into the list filter through a shared variable.
+  Hint, secondary, forward and other zones are listed again.
+- named-checkconf and named-checkzone output is classified by the tools'
+  exit code. Their warnings (e.g. `both "recursion no;" and "allow-recursion"
+  active`) were shown as errors. They are now shown as warnings in the
+  CLI, `jarld check` and the web UI.
+- The `zone_outside_view` error says how to fix it (`--adopt-zones`).
 
 ### Added
 
@@ -91,4 +99,5 @@ The first version, to be released as 0.1.0.
   end-to-end script (`scripts/e2e.sh`) that drives every CLI command
   against a running named.
 - **Documentation**: concepts, install and adoption, configuration, CLI,
-  API, permissions, ACME, validation, operations and development guides.
+  API, permissions, ACME, validation, operations and development guides, and
+  a split-DNS guide for adding views to a server that has none.