fix(agent): bound Antigravity ingestion flow

contracts/service-v1.json

@@ -1212,7 +1212,7 @@
       "name": "source_extraction_block"
     },
     {
-      "description": "Validate and submit one bounded typed proposal revision.",
+      "description": "Validate and submit one bounded proposal; report any safe input repair.",
       "input_schema": {
         "properties": {
           "proposal_json": {
@@ -1246,7 +1246,7 @@
       "name": "proposal_prepare"
     },
     {
-      "description": "Evaluate one bounded proposal without storing or publishing it.",
+      "description": "Evaluate one bounded proposal without storing or publishing it.\n\nA single missing final outer brace is repaired only if the result\nis valid JSON and matches the full contract. The response exposes\ninput_repaired=true. Other malformed JSON returns status=invalid.\nA valid proposal may instead return needs-review when an applicable\npolicy requires an owner decision.\n",
       "input_schema": {
         "properties": {
           "proposal_json": {