Never make a credential only a person can give, and give it once per provider (hq issue 164, ADR 0337)

A Servarr app's API key, an indexer's key and a downloader's password are values the provider's
software holds; the pair path made a random value for every consumer of them, sealed it to both ends
and reported success, and the provider refused it. An offer may now say `"credential": {"issued-by":
"outside"}`: SecretFor never makes a value for it, the plan reads such a pair as given or not given
and sends the consumer no credential file until a person gives it, without refusing its machine;
remakeShared and SharedSecretFor never make a provider's own secret issued outside either.
`secret accept <provider's node> <provider module> <provision>` seals one value to every consumer that
binds the provision from that provider, the provider and the operator, under one generation; the
per-pair form is refused for such a provision, and rotate names the accept. A consumer may wait for a
provision's credential: the controller excuses the wait only when the store bears it out, and its
needs-operator condition names the one accept line.

Adds the replay of issue 164 (TestReplay164), written with only what the controller had before.

cmd/mesh-controller/secret.go

@@ -79,6 +79,37 @@ func secretCommand(ctx context.Context, args []string) error {
 		return fmt.Errorf("a secret's value is given at the controller's terminal or at the desk (`give`), never "+
 			"through a verb (this line came through %q): nothing was read or sealed", verb)
 	}
+	// **A provision's credential issued outside the mesh is given once, for its provider** (novox/hq ADR 0337 §3,
+	// issue 165): `secret accept <provider's machine> <provider module> <provision>`, sealed to every consumer of
+	// that provider; the per-pair form naming a consumer is refused for it, naming this one.
+	outsideAt, err := outsideOffer(ctx, module, name, *provider)
+	if err != nil {
+		return err
+	}
+	if outsideAt == "" && *provider != "" {
+		if offered, err := offeredOutsideBy(ctx, name); err != nil {
+			return err
+		} else if offered != "" {
+			return fmt.Errorf("%s is issued outside the mesh and given once for its provider, which seals it to "+
+				"every consumer of it (ADR 0337): `secret accept %s %s %s`; nothing was read or sealed",
+				name, *provider, offered, name)
+		}
+	}
+	if outsideAt != "" {
+		if *desk != "" || *local != "" {
+			return errors.New("a provision's credential issued outside the mesh is given at the controller's " +
+				"terminal, for every consumer of its provider; it takes neither --at-desk nor --local")
+		}
+		value, err := valueFor(node, module, name, *from)
+		if err != nil {
+			return err
+		}
+		value = asSupplied(value)
+		if value == "" {
+			return errors.New("there is nothing to seal")
+		}
+		return acceptForProvision(ctx, node, module, name, value)
+	}
 	if *desk != "" {
 		if *from != "" || *provider != "" {
 			return errors.New("--at-desk gives a module's own secret, and takes neither --from nor --provider")
@@ -173,6 +204,7 @@ const secretUsage = "secret rotate <node> <module> <name> [--why <text> [--cause
 	"secret ask <node> <module> <name> [--at <machine>]\n" +
 	"secret issued <provision>\n" +
 	"secret accept <node> <module> <name> [--from <file> | --at-desk <machine>] [--provider <node> [--local <name>]]\n" +
+	"secret accept <provider's node> <provider module> <provision> [--from <file>]   (a credential issued outside the mesh, for every consumer)\n" +
 	"secret recover <node> <module> <name> --key <operator-key> [--out <file>] [--from-export <file>] [--provider <node>]\n" +
 	"secret export [--out <file>]"