Release 2.0.0 — explicit monorepo_url, drop first-target-host inference

Breaking change. The monorepo's gitea host was previously inferred from the
first target's subrepo_url, silently coupling the two and breaking on any
multi-host setup (monorepo on host A, target on host B). v2.0.0 replaces the
inference with a required josh.monorepo_url field that mirrors subrepo_url —
same parsing, same SSH/HTTPS auth options, same shape.

- schema_version: 2 is now required; v1 configs are rejected with a clear migration error
- josh.monorepo_url is required; josh.monorepo_auth is optional (default https)
- mono_auth_url() in lib/auth.sh mirrors subrepo_auth_url()
- MONOREPO_API derives from monorepo_url's host instead of .[0].gitea_host;
  env-var override preserved as escape hatch
- initial_import() and force-push call mono_auth_url() instead of building URLs inline
- ADR-012 documents the rationale; CHANGELOG includes migration snippet

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

schema/config-schema.json

@@ -3,16 +3,16 @@
   "title": "josh-sync configuration",
   "description": "Configuration for bidirectional monorepo ↔ subrepo sync via josh-proxy",
   "type": "object",
-  "required": ["josh", "targets", "bot"],
+  "required": ["schema_version", "josh", "targets", "bot"],
   "properties": {
     "schema_version": {
       "type": "integer",
-      "const": 1,
-      "description": "Schema version. Bump when config fields are removed or renamed (matches josh-sync major version)."
+      "const": 2,
+      "description": "Schema version. Required. Must be 2 for josh-sync v2.x configs."
     },
     "josh": {
       "type": "object",
-      "required": ["proxy_url", "monorepo_path"],
+      "required": ["proxy_url", "monorepo_path", "monorepo_url"],
       "properties": {
         "proxy_url": {
           "type": "string",
@@ -21,7 +21,17 @@
         },
         "monorepo_path": {
           "type": "string",
-          "description": "Repo path as josh sees it (org/repo)"
+          "description": "Repo path as josh-proxy sees it (org/repo)"
+        },
+        "monorepo_url": {
+          "type": "string",
+          "description": "Monorepo git clone URL — git@host:org/repo.git (SSH) or https://host/org/repo.git. The gitea host is derived from this URL."
+        },
+        "monorepo_auth": {
+          "type": "string",
+          "enum": ["https", "ssh"],
+          "default": "https",
+          "description": "Auth method for cloning the monorepo. SSH uses the user's ssh-agent / ~/.ssh/config; HTTPS injects ${SYNC_BOT_USER}:${SYNC_BOT_TOKEN} into the URL."
         }
       }
     },