nix: move the agent option namespace under services.hyperhive.agent

Every per-agent harness option lived at the top-level `hyperhive.*` while
the host tier has always been `services.hyperhive.*`. Move all 52 agent-tier
option leaves (33 top-level names across 16 modules) to
`services.hyperhive.agent.*`, repoint every read, and keep existing agent
configs evaluating through one `mkRenamedOptionModule` per old leaf path in
the new nix/agent-modules/renamed-options.nix.

The shims are per leaf rather than per namespace: `user`, `mcp`, `otel`,
`queue`, `docs`, `forge`, `frontend`, `github`, `gui`, `logs`, `matrix` and
`cargo` are plain attrsets of declarations, not submodule-typed options, so
a parent-path rename would not reach their children. Three read-only
options (`frontend.mergedDist`, `queue.clientIdFile`,
`queue.clientSecretFile`) deliberately get no shim — a rename contributes a
definition, which a read-only option refuses; the exclusions are commented
in place.

Refs #4473

nix/agent-modules/frontend.nix

@@ -8,9 +8,9 @@
   ...
 }:
 {
-  options.hyperhive.frontend.dist = lib.mkOption {
+  options.services.hyperhive.agent.frontend.dist = lib.mkOption {
     type = lib.types.package;
-    default = config.hyperhive.packages.frontend;
+    default = config.services.hyperhive.agent.packages.frontend;
     defaultText = lib.literalMD "`hyperhive.packages.frontend` (the flake's frontend dist)";
     description = ''
       The shipped frontend dist (built by `nix/packages/frontend.nix`).
@@ -22,18 +22,18 @@
     '';
   };
 
-  options.hyperhive.frontend.mergedDist = lib.mkOption {
+  options.services.hyperhive.agent.frontend.mergedDist = lib.mkOption {
     type = lib.types.package;
     readOnly = true;
     description = ''
       Computed: the merged static tree consumed by the harness via
       `HIVE_STATIC_DIR`. Composed at evaluation time by copying
-      `hyperhive.frontend.dist`'s `agent/` subdir as the base, then
+      `services.hyperhive.agent.frontend.dist`'s `agent/` subdir as the base, then
       layering each `extraFiles` entry on top. Read-only — do not set directly.
     '';
   };
 
-  options.hyperhive.frontend.extraFiles = lib.mkOption {
+  options.services.hyperhive.agent.frontend.extraFiles = lib.mkOption {
     type = lib.types.attrsOf (
       lib.types.submodule (
         { name, ... }:
@@ -100,7 +100,7 @@
       prior entry's target), the `mergedDist` build aborts with
       `refusing to overwrite existing path '<target>' in the
       default dist`. To override a default file, fork the dist via
-      `hyperhive.frontend.dist` instead — `extraFiles` is for
+      `services.hyperhive.agent.frontend.dist` instead — `extraFiles` is for
       pure additions.
 
       `target` must be a relative path inside the static dir. An
@@ -112,7 +112,7 @@
 
   config = {
     assertions = [
-      # hyperhive.frontend.extraFiles[*].target is concatenated into
+      # services.hyperhive.agent.frontend.extraFiles[*].target is concatenated into
       # $out during the mergedDist build. The option's strMatching
       # type already rejects leading `/`, leading `.`, and the
       # weirder characters; this assertion catches mid-path `..`
@@ -122,10 +122,10 @@
       # kind of mistake that's easy to make and hard to spot.
       {
         assertion = lib.all (entry: !(builtins.any (seg: seg == "..") (lib.splitString "/" entry.target))) (
-          lib.attrValues config.hyperhive.frontend.extraFiles
+          lib.attrValues config.services.hyperhive.agent.frontend.extraFiles
         );
         message = ''
-          hyperhive.frontend.extraFiles: `target` must not contain
+          services.hyperhive.agent.frontend.extraFiles: `target` must not contain
           `..` path segments.
         '';
       }
@@ -137,20 +137,22 @@
     # filename collision with the default dist surfaces as a build
     # failure rather than a silent override (operator gets a clear
     # nix error rather than a confusing 404 / silent dist swap).
-    hyperhive.frontend.mergedDist = pkgs.runCommand "hyperhive-agent-frontend-merged" { } (
-      ''
-        mkdir -p $out
-        cp -r ${config.hyperhive.frontend.dist}/agent/. $out/
-        chmod -R u+w $out
-      ''
-      + lib.concatMapStrings (entry: ''
-        mkdir -p $(dirname $out/${entry.target})
-        if [ -e $out/${entry.target} ]; then
-          echo "hyperhive.frontend.extraFiles: refusing to overwrite existing path '${entry.target}' in the default dist" >&2
-          exit 1
-        fi
-        cp -r ${entry.source} $out/${entry.target}
-      '') (lib.attrValues config.hyperhive.frontend.extraFiles)
-    );
+    services.hyperhive.agent.frontend.mergedDist =
+      pkgs.runCommand "hyperhive-agent-frontend-merged" { }
+        (
+          ''
+            mkdir -p $out
+            cp -r ${config.services.hyperhive.agent.frontend.dist}/agent/. $out/
+            chmod -R u+w $out
+          ''
+          + lib.concatMapStrings (entry: ''
+            mkdir -p $(dirname $out/${entry.target})
+            if [ -e $out/${entry.target} ]; then
+              echo "services.hyperhive.agent.frontend.extraFiles: refusing to overwrite existing path '${entry.target}' in the default dist" >&2
+              exit 1
+            fi
+            cp -r ${entry.source} $out/${entry.target}
+          '') (lib.attrValues config.services.hyperhive.agent.frontend.extraFiles)
+        );
   };
 }