hive-c0re: render the new agent option paths into generated agent flakes

meta.rs writes each agent's flake, and it still named the pre-move
`hyperhive.*` paths — so every agent rebuild would print a rename
deprecation warning about a line no human wrote and no operator could fix.
A warning nobody can act on trains everyone to ignore the ones that matter,
which is the whole value of the alias shims.

Repoints the FORWARDED_VAR_OPTIONS table and every other emitted option
assignment (otel.*, docs.source, claudeCodePath, github.enable, user.name,
claudeMemoryMaxBytes) to `services.hyperhive.agent.*`, with the test
expectations that pin the rendered text. The flake input named `hyperhive`
(`hyperhive.url`, `hyperhive.inputs.nixpkgs.follows`,
`hyperhive.nixosConfigurations.*`), hive-tier `services.hyperhive.*` paths,
and the `@hyperhive.local` git identity share the word and are untouched.

Also repoints the same option paths where they appear in comments, rustdoc
and runtime message strings across the other crates — a refusal message
naming `hyperhive.allowedRecipients` sends an operator to a path that will
stop existing. Prose under docs/ is deliberately not in this commit.

Refs #4473

hive-c0re/src/container_view.rs

@@ -202,7 +202,7 @@ pub async fn build_all(hive: &crate::coordinator::HiveEnv) -> Vec<ContainerView>
         // stale sentinel state is not meaningful when the harness isn't up.
         //
         // The first half doesn't apply to an api-key agent
-        // (`hyperhive.useApiKey`, stamped as `api_key_mode` in the
+        // (`services.hyperhive.agent.useApiKey`, stamped as `api_key_mode` in the
         // consolidated state file by `hive_agent::harness_state::write_api_key_mode`):
         // its `~/.claude/` is empty by design (no OAuth flow to complete),
         // so an empty dir there means nothing — only the auth-failed