fix: send ISO format dates instead of Unix timestamps

Backend was sending Unix timestamps as strings (e.g. '1716112800')
which JavaScript Date couldn't parse. Now sends proper ISO 8601
format dates that work with new Date() in the browser.

apps/api/src/utils/git_history.py

@@ -2,6 +2,7 @@
 
 import subprocess
 from dataclasses import dataclass
+from datetime import datetime, timezone
 from typing import Any
 
 
@@ -182,10 +183,10 @@ def get_commit_detail(repo_path: str, commit_hash: str) -> dict[str, Any]:
         "parents": parents,
         "author_name": author,
         "author_email": email,
-        "author_date": str(timestamp),
+        "author_date": datetime.fromtimestamp(timestamp, tz=timezone.utc).isoformat(),
         "committer_name": author,  # TODO: extract committer separately
         "committer_email": email,  # TODO: extract committer separately
-        "committer_date": str(timestamp),
+        "committer_date": datetime.fromtimestamp(timestamp, tz=timezone.utc).isoformat(),
         "message": message,
         "body": body,
         "branches": branch_map.get(commit_hash, []),
@@ -361,7 +362,7 @@ def _commit_to_dict(commit: Commit, graph_symbol: str = "", graph_depth: int = 0
         "parents": commit.parents,
         "author_name": commit.author,
         "author_email": commit.email,
-        "author_date": str(commit.timestamp),
+        "author_date": datetime.fromtimestamp(commit.timestamp, tz=timezone.utc).isoformat(),
         "message": commit.message,
         "refs": refs,
         "graph_symbol": graph_symbol,