Share the target filter, fix cd-status branch, record deploy status

- enabled_targets/names_for: one implementation of 'a host acts only on its
  own targets'; --host s5 and --host s5.fisher.hu now select the same targets
- shell_value: JSON booleans reach shell consumers as true/false
- cd-status: capture before eval, so the unconfigured-host branch is reachable
- cd-deploy writes a .status record; cd-status reads it instead of grepping
  the log's prose
- cd-render-hooks --list-urls replaces two inline JSON readers

docs/OPERATIONS.md

@@ -21,7 +21,7 @@ deploy ended.
 | This repository | `~/S/my-cd-webhook` |
 | Secrets (0600) | `~/.config/cd-webhook/secrets.env` |
 | Rendered hooks (0600, generated) | `~/.config/cd-webhook/hooks.json` |
-| Deploy logs and locks | `~/.local/state/cd-webhook/<target>.log` |
+| Deploy logs, locks, last-deploy records | `~/.local/state/cd-webhook/<target>.{log,lock,status}` |
 | systemd unit | `~/.config/systemd/user/cd-webhook.service` |
 
 ```bash
@@ -74,7 +74,7 @@ missed deploy, not a wrong one.
 ## Adding a host
 
 1. Add the host to `"hosts"` in `targets.json` with its WireGuard address and
-   port `21600`.
+   the same port the other hosts there use.
 2. Add its targets.
 3. Commit and push this repository.
 4. On the host: clone, `./install/install.sh`, fill in `secrets.env`, re-run.

docs/hints.md

@@ -7,6 +7,13 @@ Short notes on things that were not obvious. Prune stale ones.
   `importlib.machinery.SourceFileLoader`. Importing `importlib.util` alone is
   not enough — `importlib.machinery` needs its own import.
 
+- **`if eval "$(cmd)"` tests the wrong thing.** `eval` reports the status of the
+  string it evaluates, and an empty string is success — so a failing `cmd` makes
+  the `if` take the *true* branch with nothing assigned, and `set -u` then aborts
+  on the first variable the branch reads. Capture first
+  (`if out="$(cmd)"; then eval "$out"`). This had made `cd-status`'s "host is not
+  configured" message unreachable.
+
 - **`docker/metadata-action`'s `type=sha,format=short` produces 7 characters.**
   That is why `image_tag_template` uses `{short7}`. domaindingo's `build.yml`
   prefixes it with the branch, giving `test-sha-abc1234` / `prod-sha-abc1234`.