modules/{policy,view}: do not act if FAIL or DONE

Not all actions are destructive, but it seems generally expected that if
an earlier module or other code already transitioned the request into
a FAIL or DONE state, we don't want to apply rules anymore.
In particular, later rule actions would "overwrite" what previous
actions did.

modules/policy/policy.lua

@@ -549,12 +549,18 @@ end
 -- as a dependency chain, e.g. r1,r2,r3 -> r3(r2(r1(state)))
 policy.layer = {
 	begin = function(state, req)
+		-- Don't act on "resolved" cases.
+		if bit.band(state, bit.bor(kres.FAIL, kres.DONE)) ~= 0 then return state end
+
 		req = kres.request_t(req)
 		return policy.evaluate(policy.rules, req, req:current(), state) or
 		       policy.evaluate(policy.special_names, req, req:current(), state) or
 		       state
 	end,
 	finish = function(state, req)
+		-- Don't act on "resolved" cases.
+		if bit.band(state, bit.bor(kres.FAIL, kres.DONE)) ~= 0 then return state end
+
 		req = kres.request_t(req)
 		return policy.evaluate(policy.postrules, req, req:current(), state) or state
 	end

modules/view/view.lua

@@ -106,7 +106,9 @@ end
 -- @function Module layers
 view.layer = {
 	begin = function(state, req)
-		if state == kres.FAIL then return state end
+		-- Don't act on "resolved" cases.
+		if bit.band(state, bit.bor(kres.FAIL, kres.DONE)) ~= 0 then return state end
+
 		req = kres.request_t(req)
 		evaluate(state, req)
 		return req.state