remove the create_repo agent tool

mara ruled on #4849 (c88934): "remove create_repo tool". The tool ran in
hive-c0re with the hive's core token, so it only ever worked for agents
on the hive that runs the forge.

Removed:

- the create_repo MCP tool and CreateRepoArgs (hive-agent-mcp)
- wire variants Request::CreateRepo and Response::RepoCreated
  (hive-core-agent-sock)
- hive-c0re's handle_create_repo, its valid_repo_name check and the
  dispatch arm
- forge::create_agent_repo and apply_operator_branch_protection, which
  had no other caller, plus AGENTS_ORG and OPERATORS_TEAM, whose only
  users they were
- the tool's docs (docs/tools/forge.md repo management, docs/turn-loop/
  mcp.md, the conventions tool-group table) and the doc comments that
  named it (hive-sock-client's response timeout, ensure_repo_creation_
  disabled, the security doc's merge-gate bullet)

ToolGroup::Forge is kept with no tools, the same way b88a5b24 kept
Lifecycle, so existing meta/capabilities.json grants still parse.

Forge state is untouched: existing agents/* repos keep their collaborators
and operators-team branch protection. The swarm-controller's own
create_repo (config-org repos) is a different path and is unchanged.

Closes #4849

hive-c0re/src/forge/repos.rs

@@ -18,8 +18,8 @@ use reqwest::StatusCode;
 use crate::coordinator::Coordinator;
 
 use super::{
-    AGENTS_ORG, CONFIG_ORG, OPERATORS_TEAM, SHARED_DOCS_REPO, SHARED_ORG, api, core_auth_header,
-    core_token, forge_git_url, forge_http_base, is_present,
+    CONFIG_ORG, SHARED_DOCS_REPO, SHARED_ORG, api, core_auth_header, core_token, forge_git_url,
+    forge_http_base, is_present,
 };
 
 /// Creation options for an empty repo defaulting to `main`.
@@ -659,52 +659,6 @@ fn main_branch_protection_option() -> CreateBranchProtectionOption {
     }
 }
 
-/// Apply the operator merge-gate branch protection to `repo`'s default
-/// branch: only [`OPERATORS_TEAM`] members can merge, and an
-/// approving review from that team is required — so the author (a write-level
-/// agent, not in the team) cannot merge its own PR.
-///
-/// Idempotent, but **verify-don't-trust**: a create failure is ambiguous —
-/// "rule already exists" (success) OR a silent rejection that created NO rule
-/// (e.g. a 422 where `OPERATORS_TEAM` doesn't exist in `AGENTS_ORG`). The old
-/// code folded 200/409/422 into `Ok` and left the repo unprotected with no
-/// error — a fail-open merge gate. So on any create error, GET the `main` rule
-/// and only treat it as success if the rule is actually present (the exact fix
-/// already applied to [`apply_config_repo_branch_protection`]).
-async fn apply_operator_branch_protection(repo: &str, token: &str) -> Result<()> {
-    let client = api(token)?;
-    let mut rule = main_branch_protection_option();
-    rule.enable_merge_whitelist = Some(true);
-    rule.merge_whitelist_teams = Some(vec![OPERATORS_TEAM.to_owned()]);
-    rule.enable_approvals_whitelist = Some(true);
-    rule.approvals_whitelist_teams = Some(vec![OPERATORS_TEAM.to_owned()]);
-    rule.required_approvals = Some(1);
-    rule.block_on_official_review_requests = Some(true);
-    let Err(create_err) = client
-        .repo_create_branch_protection(AGENTS_ORG, repo, rule)
-        .await
-    else {
-        tracing::info!(%repo, "forge: applied operator branch protection");
-        return Ok(());
-    };
-    match client
-        .repo_get_branch_protection(AGENTS_ORG, repo, "main")
-        .await
-    {
-        Ok(_) => {
-            tracing::debug!(
-                %repo, create_error = %create_err,
-                "forge: operator branch protection already present"
-            );
-            Ok(())
-        }
-        Err(check_err) => anyhow::bail!(
-            "branch protection for {AGENTS_ORG}/{repo} not applied: create failed \
-             ({create_err}); GET main rule failed ({check_err}), no `main` rule present"
-        ),
-    }
-}
-
 /// Apply branch protection to an `agent-configs/<name>` repo's `main` so it
 /// can serve as the agent-editable, PR-merge config surface:
 /// - **`main` is never directly pushable** — no push is enabled on the
@@ -809,24 +763,3 @@ fn config_repo_protection_edit() -> EditBranchProtectionOption {
         unprotected_file_patterns: None,
     }
 }
-
-/// Create a repo for `agent` in the c0re-owned [`AGENTS_ORG`] and wire the
-/// perms: the org owns it (perms stay c0re-managed), the agent is added
-/// as a **write** collaborator (not owner — can push + open PRs but can't
-/// bypass branch protection), and the default branch gets the operator
-/// merge gate. This is the sanctioned create path now that agents can't
-/// create repos directly (`max_repo_creation = 0`). Idempotent.
-pub async fn create_agent_repo(agent: &str, repo: &str, core_token: &str) -> Result<String> {
-    ensure_org_repo(AGENTS_ORG, repo, core_token).await?;
-    add_collaborator(
-        AGENTS_ORG,
-        repo,
-        agent,
-        AddCollaboratorOptionPermission::Write,
-        core_token,
-    )
-    .await?;
-    apply_operator_branch_protection(repo, core_token).await?;
-    tracing::info!(%agent, %repo, "forge: created agent repo in {AGENTS_ORG} with operator merge gate");
-    Ok(format!("{AGENTS_ORG}/{repo}"))
-}