refactor: move hive-c0re options to hyperhive namespace (#612)

- Move options.services.hive-c0re → options.hyperhive.c0re
- Add options.hyperhive.enable to auto-enable c0re + subsystems
- Add deprecation alias for services.hive-c0re.enable (backward compat)
- Update doc references in README, flake.nix, docs, harness-base.nix
- Simplifies config: 'hyperhive.enable = true' now enables everything

Existing operator configs using services.hive-c0re.enable will
continue to work but emit a deprecation warning. Aligns the option
namespace with the existing hyperhive.* family (matrix, forge, domain).

fixes #612

docs/turn-loop.md

@@ -76,7 +76,7 @@ match wins):
 
 1. `HIVE_CONTEXT_WINDOW_TOKENS_<KEY>` env var, where `KEY`
    (lowercased) is a substring of the active model name. Injected
-   by the meta flake from `services.hive-c0re.contextWindowTokens`
+   by the meta flake from `hyperhive.c0re.contextWindowTokens`
    (host-level NixOS option, defaults: haiku=200k, sonnet=1M,
    opus=1M). Override these for all agents at once without a
    per-agent config change.
@@ -178,7 +178,7 @@ socket at `/run/hive/` once at startup:
   #519); everything else is shared. Then `{label}` and
   `{operator_pronouns}` get substituted in the assembled output.
   Pronouns come from `HIVE_OPERATOR_PRONOUNS` env (set by the meta
-  flake from `services.hive-c0re.operatorPronouns`, default
+  flake from `hyperhive.c0re.operatorPronouns`, default
   `she/her`). Passed via `--system-prompt-file`.
 
 The shared per-turn plumbing lives in `hive_ag3nt::turn::{write_mcp_config,