Initial implementation: AI code review bot for Gitea

- CLI binary with flag/env var configuration
- Gitea API client (PR metadata, diff, CI status, post review)
- OpenAI-compatible LLM client
- Structured review prompt with conventions support
- JSON response parser with validation
- Markdown review formatter for Gitea
- CI failure auto-detection (REQUEST_CHANGES)
- Dry-run mode for testing

review/parser.go

@@ -0,0 +1,76 @@
+package review
+
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+// Finding represents a single code review finding.
+type Finding struct {
+	Severity string `json:"severity"`
+	File     string `json:"file"`
+	Line     int    `json:"line"`
+	Finding  string `json:"finding"`
+}
+
+// ReviewResult is the structured output from the LLM.
+type ReviewResult struct {
+	Verdict        string    `json:"verdict"`
+	Summary        string    `json:"summary"`
+	Findings       []Finding `json:"findings"`
+	Recommendation string    `json:"recommendation"`
+}
+
+// ParseResponse parses the LLM response into a ReviewResult.
+func ParseResponse(response string) (*ReviewResult, error) {
+	// Try to extract JSON from the response — the LLM might wrap it in markdown fences
+	cleaned := extractJSON(response)
+
+	var result ReviewResult
+	if err := json.Unmarshal([]byte(cleaned), &result); err != nil {
+		return nil, fmt.Errorf("parse LLM response as JSON: %w\nRaw response: %s", err, response)
+	}
+
+	// Validate verdict
+	switch result.Verdict {
+	case "APPROVE", "REQUEST_CHANGES":
+		// valid
+	default:
+		return nil, fmt.Errorf("invalid verdict %q (must be APPROVE or REQUEST_CHANGES)", result.Verdict)
+	}
+
+	// Validate finding severities
+	for i, f := range result.Findings {
+		switch f.Severity {
+		case "MAJOR", "MINOR", "NIT":
+			// valid
+		default:
+			return nil, fmt.Errorf("finding %d has invalid severity %q", i, f.Severity)
+		}
+	}
+
+	return &result, nil
+}
+
+// extractJSON attempts to pull JSON from a potentially markdown-wrapped response.
+func extractJSON(s string) string {
+	s = strings.TrimSpace(s)
+
+	// Remove markdown code fences if present
+	if strings.HasPrefix(s, "```") {
+		lines := strings.Split(s, "\n")
+		// Remove first line (```json or ```)
+		if len(lines) > 2 {
+			lines = lines[1:]
+		}
+		// Remove last line (```)
+		if len(lines) > 0 && strings.TrimSpace(lines[len(lines)-1]) == "```" {
+			lines = lines[:len(lines)-1]
+		}
+		s = strings.Join(lines, "\n")
+	}
+
+	s = strings.TrimSpace(s)
+	return s
+}