fix(harnesses): migrate to ESO secrets_required form, mirror agent-runtimes

The CRS-served harnesses still carried `secrets_files: [{encrypted: true}]`
which now hard-fails on H-SECRET-1 ("SOPS-encrypted secrets_files entries
are no longer permitted") in the dispatcher's harness validator. Sync the
8 provider harnesses with the agent-runtimes copies: same `secrets_required`
shape, same `init.sh` (ESO-mounted file paths), same `bin/` wrappers.

Use bare `account_ref: "<provider>"` (not `<provider>.cp:cp` — that
scope-kind isn't valid per SR-DISP-1-FIELD).

Provider key names follow the per-provider schema as emitted by the CP
provisioner: minimax/airouter/z-ai → api_key; gitea-https/gitea-admin →
{token,base_url,username}; gitea-ssh* → {host,private_key}.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

harnesses/contexts/gitea-admin/v1/init.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+# init.sh for gitea-admin harness (M22 Phase 9)
+# Sets up non-secret env vars and configures git credential helper.
+# Credential token is NOT exported here — only read at exec time by the wrapper.
+
+set -euo pipefail
+
+# Non-secret configuration
+export GITEA_BASE_URL="${GITEA_BASE_URL:-https://gitea.oreillyit.nz}"
+
+# Ensure SSH directory exists with correct permissions
+mkdir -p /home/agent/.ssh
+chmod 700 /home/agent/.ssh
+
+# Configure git to use the gitea-admin credential helper wrapper
+# The wrapper reads the ESO-mounted token at exec time
+git config --global credential.helper "!/opt/harness/contexts/gitea-admin/v1/bin/gitea-admin-wrapper.sh git-credential-helper"
+
+echo "[gitea-admin] init complete"