fix(review): language-tagged suggestion fence for Gitea syntax highlighting

Gitea 1.26.x has no GitHub-style 'Apply suggestion' button — a ```suggestion
fence is just an unknown-language code block, so chroma does not highlight it
and there is no apply control. Switch inline_comment_body to wrap the suggested
fix in a fence tagged with the file's language (new _lang_for_path helper,
.java→java, .ts→typescript, .py→python, ...), so Gitea syntax-highlights the
code. No capability lost (there was never an apply button on this Gitea
version). Correct the docstrings/skills/README that wrongly claimed an
apply-button was rendered.

Co-Authored-By: Claude <noreply@anthropic.com>

.opencode/README.md

@@ -6,7 +6,7 @@ checked-out copy of the target repo at the PR head sha, then `opencode run` is
 launched there. The `pragent` primary agent reviews the diff with real tools
 (subagents, LSP/linters via bash, webfetch references) and emits a structured
 findings JSON. A thin Python shell posts that JSON back to Gitea as inline
-comments + ```suggestion blocks + a summary (dedupe + anchor validation stay
+comments + language-highlighted suggested-fix blocks + a summary (dedupe + anchor validation stay
 deterministic in Python).
 
 ## Layout
@@ -40,7 +40,7 @@ flowchart TD
   PR --> JSON["final message: summary + ```json findings```"]
   JSON --> PARSE["ai_review.parse_review_output<br/>{summary, findings}"]
   PARSE --> ANCHOR["parse_diff_anchors → split_findings"]
-  ANCHOR --> POST["post_inline_review<br/>summary + inline ```suggestion + ref links + sha marker"]
+  ANCHOR --> POST["post_inline_review<br/>summary + inline lang-tagged fix block + ref links + sha marker"]
 ```
 
 ## Lean by default