bazarr: reach sonarr and radarr through the mesh; placed dirs; the image ace runs

bazarr reached sonarr and radarr as `sonarr:8989` and `radarr:7878`,
container names on HAL's shared network, which the mesh does not have.
It now requires sonarr-api and radarr-api (provided since #156) and a
run-once step writes host, port, TLS, base path and key into bazarr
through bazarr's own POST /api/system/settings - the call its settings
screen makes - only for the fields that differ, and reads them back.
bazarr's config.yaml is not written by the mesh: bazarr holds it in
memory and rewrites it, so the two would overwrite each other. The key is
tried against the app first; a refused key (a minted pair credential
before the operator accepts the app's own) is never written, and the step
fails naming the `secret accept` that fixes it. Declared last so its
failing gates nothing else (ADR 0136); restart-on its four inputs.

The api-key own-secret is gone. bazarr makes its own key and nothing lets
the mesh set it, so a minted one could never work; the tools and the step
read auth.apikey from bazarr's own config/config.yaml (mounted read-only),
which also stays right if the key is regenerated. Nothing to accept.

The config dir is a pathless ${dir:config}; config.json and the bindings
live in a placed state dir; /var/lib/mesh/bazarr keeps only the broker.
The image is pinned to the digest ace runs (v1.6.1-ls364); the old pin was
v1.6.0-ls361, older than ace's database.

Based on feat/servarr-api-provision (#156); this branch contains it.

Verified: catalogue tests with MESH_CATALOGUE pass (not skipped); a
resolve of sonarr+radarr+bazarr on a fake ace renders both bindings and
sealed credentials into the state dir with every ${} filled, and bazarr
alone is refused naming sonarr and radarr; strict tsc passes and the
Dockerfile's non-strict compile builds; 8 node tests pass; the compiled
step against the pinned image in a throwaway container with fake
sonarr/radarr wrote sonarr (ip, port, apikey), refused radarr's minted
key and wrote nothing for it, wrote radarr once the key was right, and
changed nothing on a third run - the values landed in config.yaml.

modules/bazarr/apikey.ts

@@ -0,0 +1,37 @@
+// bazarr's own API key, found where bazarr keeps it. Shared by the client (tools, events) and the
+// Servarr step, and kept apart from client.ts so the step and its test load it without the client.
+
+import { readFileSync } from "node:fs";
+
+/**
+ * bazarr's own API key, read from where bazarr keeps it: `auth.apikey` in `config/config.yaml` under
+ * its config directory. bazarr makes this key itself on first start and nothing lets the mesh set it,
+ * so a key the mesh minted could never work; reading bazarr's own file needs nothing accepted and
+ * stays right if the operator regenerates the key in bazarr's settings screen. The file is read, never
+ * written. Undefined when the file or the key is not there.
+ */
+export function apiKeyFromConfigDir(configDir?: string): string | undefined {
+  if (!configDir) return undefined;
+  let text: string;
+  try { text = readFileSync(`${configDir.replace(/\/$/, "")}/config/config.yaml`, "utf8"); }
+  catch { return undefined; }
+  return apiKeyFromConfigYaml(text);
+}
+
+/** `auth.apikey` from the text of bazarr's config.yaml — a top-level `auth:` mapping, one level deep. */
+export function apiKeyFromConfigYaml(text: string): string | undefined {
+  let inAuth = false;
+  for (const line of text.split(/\r?\n/)) {
+    if (/^\S/.test(line)) {
+      inAuth = /^auth:\s*$/.test(line);
+      continue;
+    }
+    if (!inAuth) continue;
+    const m = line.match(/^\s+apikey:\s*(.*?)\s*$/);
+    if (m) {
+      const v = m[1].replace(/^(['"])(.*)\1$/, "$2").trim();
+      return v || undefined;
+    }
+  }
+  return undefined;
+}