fix: validate Gitea conversation caches and safe commit messages

harness/agents/impl/skills/gitea-issue-rework/references/readback.md

@@ -36,28 +36,52 @@ pre-write delegation admission.
 Schema: `gitea-agent.rework-provider/v1`. The contract explicitly declares the
 aggregate semantics for PR and underlying PR-Issue `comments` fields. Each
 `components` array contains unique values from `top_level`, `reviews`, `inline`
-and must include `top_level`. Choose the reviewed deployment semantics, not the
+and must include `top_level`. An optional `cache_mode: "gitea-conversation-v1"`
+on each aggregate scope is accepted only for provider version `1.27.3`, field
+`comments`, and components consisting of exactly `top_level` and `reviews`.
+Omission retains strict legacy behavior. Choose the reviewed deployment semantics, not the
 combination that happens to fit a current response. There is no guessed version
 or automatic capability downgrade.
 
-Shape example only, **not a claim about this deployment**:
+Shape example only: upstream v1.27.3 source supports this shape; it does not attest that a custom build matches upstream:
 
 ```json
 {
   "schema": "gitea-agent.rework-provider/v1",
-  "version": "<independently-observed-version>",
+  "version": "1.27.3",
   "aggregate": {
-    "pr": {"field": "comments", "components": ["top_level"]},
-    "pr_issue": {"field": "comments", "components": ["top_level"]}
+    "pr": {"field": "comments", "components": ["top_level", "reviews"], "cache_mode": "gitea-conversation-v1"},
+    "pr_issue": {"field": "comments", "components": ["top_level", "reviews"], "cache_mode": "gitea-conversation-v1"}
   },
   "inline": {
     "mode": "per_review",
     "field": "review_comments",
-    "components": ["inline"]
+    "components": ["reviews"]
   }
 }
 ```
 
+### Cached conversation admission
+
+For the explicit cache mode, snapshot counters must be present non-boolean,
+nonnegative integers no greater than the complete collection-derived conversation
+count. This admits bounded stale lag, not arbitrary mismatch; counters ahead of
+the collected count, missing values and malformed scalars remain BLOCK.
+Upstream `v1.27.3` `services/convert/issue.go` reads stored `Issue.NumComments`.
+`models/issues/comment.go` counts plain comments and review-summary comments;
+review creation bypasses the recomputation that plain-comment creation performs.
+This source pin explains the opt-in policy, not a deployed custom-build attestation.
+
+For `create`, fresh readback must prove exactly one canonical top-level addition
+and the recomputed aggregate must equal the complete post-write conversation
+count. A stale baseline counter `0` with one review can become `2` after the new
+plain comment; `before counter + 1` is not the cache-mode rule. All old rows,
+reviews, inline evidence, Source Issue metadata/comments, identity, body, head
+and unrelated native fields retain their existing protections. For `reuse`, no
+addition or counter/metadata refresh is admitted: even a legitimate-looking
+cache change without the authorized create action is BLOCK. Strict contracts
+without cache opt-in retain exact snapshot projections and the original delta.
+
 For `inline.components`, the explicit projection modes are `["inline"]`,
 `["reviews"]`, and `["reviews", "inline"]`. The review-only mode projects
 only the number of reviews into `review_comments`; it does not add per-review