feat: block vague-reference issue creation with content preflight (Closes #582)

Add a pre-create content gate to gitea_create_issue that fails closed with
BLOCKED + DIAGNOSE when the title/body is a vague reference to out-of-band
draft content ("the drafted issue", "the prepared issue", "the issue we
discussed", "the previous draft") and no durable source pointer (existing
issue/PR/comment, checked-in file, URL, or scratchpad path) is present.

- issue_content_gate.py: assess_issue_content / pre_create_issue_content_gate
  with vague-phrase detection, durable-source-pointer escape hatch, and a
  domination check so long specific bodies are not falsely blocked.
- gitea_create_issue: runs the gate after preflight purity, before duplicate
  search; new allow_incomplete_content override (off by default). Title-only
  creation stays allowed (no empty-body requirement) to preserve behavior.
- tests/test_issue_content_gate.py: unit + MCP integration coverage.
- create-issue.md: documents the enforced preflight with valid/invalid
  prompt examples.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

gitea_mcp_server.py

@@ -799,6 +799,7 @@ import gitea_audit  # noqa: E402
 import gitea_config  # noqa: E402
 import capability_stop_terminal  # noqa: E402
 import issue_duplicate_gate  # noqa: E402
+import issue_content_gate  # noqa: E402
 import role_session_router  # noqa: E402
 import role_namespace_gate  # noqa: E402
 import task_capability_map  # noqa: E402
@@ -1623,6 +1624,7 @@ def gitea_create_issue(
     require_workflow_labels: bool = False,
     allow_duplicate_override: bool = False,
     split_from_issue: int | None = None,
+    allow_incomplete_content: bool = False,
     worktree_path: str | None = None,
 ) -> dict:
     """Create a new issue on a Gitea repository.
@@ -1642,6 +1644,8 @@ def gitea_create_issue(
             type:* and one status:* label.
         allow_duplicate_override: Operator-approved split after duplicate found.
         split_from_issue: Existing duplicate issue number when overriding.
+        allow_incomplete_content: Operator override to bypass the #582 content
+            gate (create despite vague/missing title/body). Off by default.
         worktree_path: Optional path to verify branches-only guard.
 
     Returns:
@@ -1670,6 +1674,25 @@ def gitea_create_issue(
     if blocked:
         return blocked
     verify_preflight_purity(remote, worktree_path=worktree_path, task="create_issue")
+    content_gate = issue_content_gate.pre_create_issue_content_gate(
+        title,
+        body,
+        allow_incomplete=allow_incomplete_content,
+    )
+    if not content_gate.get("performed"):
+        return {
+            "success": False,
+            "performed": False,
+            "number": None,
+            "content_gate": content_gate,
+            "reasons": [
+                "BLOCKED + DIAGNOSE: issue content is a vague reference or "
+                "missing required fields; provide full title/body or a durable "
+                "source pointer (existing issue/PR/comment, checked-in file, "
+                "URL, or scratchpad path). "
+                + content_gate.get("diagnose", ""),
+            ],
+        }
     base = repo_api_url(h, o, r)
     requested_labels = issue_workflow_labels.labels_for_new_issue(
         issue_type=issue_type,