fix: address review findings (comment, marker budget, naming)

- UserMeta comment: "never trimmed" → "truncated only if base exceeds budget"
- Skip diff truncation marker when diffBudget < markerBudget (prevents
  marker itself from pushing EstTokens over the limit)
- Rename filepath → filePath to avoid shadowing stdlib package name

budget/budget.go

@@ -65,7 +65,7 @@ type Sections struct {
 	Conventions string // Repo conventions (trimmed second)
 	FileContext string // Full file content (trimmed third)
 	Diff        string // The actual diff (trimmed last, only truncated)
-	UserMeta    string // PR title, description, CI status (never trimmed)
+	UserMeta    string // PR title, description, CI status (truncated only if base exceeds budget)
 }
 
 // Result holds the trimmed content and metadata about what was dropped.
@@ -154,7 +154,11 @@ func Fit(model string, sections Sections) Result {
 			removed := EstimateTokens(sections.Diff) - diffBudget
 			trimmed = append(trimmed, fmt.Sprintf("diff truncated (~%dK tokens removed)", removed/1000))
 			if maxChars > 0 {
-				sections.Diff = truncateUTF8(sections.Diff, maxChars) + diffTruncMarker
+				if diffBudget >= markerBudget {
+					sections.Diff = truncateUTF8(sections.Diff, maxChars) + diffTruncMarker
+				} else {
+					sections.Diff = truncateUTF8(sections.Diff, maxChars)
+				}
 			} else {
 				sections.Diff = diffTooLargeMarker
 			}

cmd/review-bot/main.go

@@ -255,12 +255,12 @@ func fetchPatterns(ctx context.Context, client *gitea.Client, patternsRepo, patt
 				continue
 			}
 
-			for filepath, content := range files {
+			for filePath, content := range files {
 				// Only include markdown and text files as patterns
-				if !isPatternFile(filepath) {
+				if !isPatternFile(filePath) {
 					continue
 				}
-				sb.WriteString(fmt.Sprintf("### %s/%s\n\n%s\n\n", repoRef, filepath, content))
+				sb.WriteString(fmt.Sprintf("### %s/%s\n\n%s\n\n", repoRef, filePath, content))
 			}
 		}
 	}