Add commit SHA linking to file view comments

Co-authored-by: alexr00 <38270282+alexr00@users.noreply.github.com>

Author: Copilot

src/github/prComment.ts

@@ -421,6 +421,38 @@ ${lineContents}
 		return replaceImages(body, html, this.githubRepository?.remote.host);
 	}
 
+	private replaceCommitShas(body: string): string {
+		const githubRepository = this.githubRepository;
+		if (!githubRepository) {
+			return body;
+		}
+
+		// Match commit SHAs that are:
+		// - Either 7 or 40 hex characters
+		// - Not already part of a URL or markdown link
+		// - Not inside code blocks (backticks)
+		const commitShaRegex = /(?<![`\/\w])([0-9a-f]{7})([0-9a-f]{33})?(?![`\/\w])/g;
+
+		return body.replace(commitShaRegex, (match, shortSha, remaining, offset) => {
+			// Don't replace if inside code blocks
+			const beforeMatch = body.substring(0, offset);
+			const backtickCount = (beforeMatch.match(/`/g)?.length ?? 0);
+			if (backtickCount % 2 === 1) {
+				return match;
+			}
+
+			// Don't replace if already part of a markdown link
+			if (beforeMatch.endsWith('[') || body.substring(offset + match.length).startsWith(']')) {
+				return match;
+			}
+
+			const owner = githubRepository.remote.owner;
+			const repo = githubRepository.remote.repositoryName;
+			const commitUrl = `https://${githubRepository.remote.host}/${owner}/${repo}/commit/${match}`;
+			return `[${shortSha}](${commitUrl})`;
+		});
+	}
+
 	private replaceNewlines(body: string) {
 		return body.replace(/(?<!\s)(\r\n|\n)/g, '  \n');
 	}
@@ -463,7 +495,8 @@ ${lineContents}
 			return `${substring.startsWith('@') ? '' : substring.charAt(0)}[@${username}](${url})`;
 		});
 
-		const permalinkReplaced = await this.replacePermalink(linkified);
+		const commitShasReplaced = this.replaceCommitShas(linkified);
+		const permalinkReplaced = await this.replacePermalink(commitShasReplaced);
 		await emojiPromise;
 		return this.postpendSpecialAuthorComment(emojify(this.replaceImg(this.replaceSuggestion(permalinkReplaced))));
 	}