🚧 Update commit message format

src/git_auto_tracker/application.py

@@ -171,7 +171,12 @@ class ApplicationController:
                 "Author resolved: %s -> %s", record.path, result.identifier
             )
 
-        message = build_commit_message(kept, run, app_version=_APP_VERSION)
+        message = build_commit_message(
+            kept,
+            run,
+            app_version=_APP_VERSION,
+            file_separator=self.config.commit.file_separator,
+        )
 
         if dry_run:
             log.info("Dry-run: repository left unmodified")

src/git_auto_tracker/commits/message_builder.py

@@ -2,13 +2,17 @@
 
 Human-readable sections first, Git trailer block last so that
 `git interpret-trailers` can extract the structured metadata.
+
+Each changed file occupies exactly ONE line in `git diff --name-status`
+style: a change letter followed by path, author and last-modified time,
+joined by a configurable separator (commit.file_separator, default ';').
 """
 
 from __future__ import annotations
 
 import datetime as dt
 
-from git_auto_tracker.changes.models import ChangeSet, TrackerRun
+from git_auto_tracker.changes.models import ChangeRecord, ChangeSet, ChangeType, TrackerRun
 
 _SUMMARY_LABELS = (
     ("Added:", "added"),
@@ -17,6 +21,13 @@ _SUMMARY_LABELS = (
     ("Renamed:", "renamed"),
 )
 
+_GIT_LETTER = {
+    ChangeType.ADDED: "A",
+    ChangeType.MODIFIED: "M",
+    ChangeType.DELETED: "D",
+    ChangeType.RENAMED: "R",
+}
+
 
 def _format_ts(moment: dt.datetime | None) -> str:
     """Render an aware datetime in local time with an explicit offset.
@@ -30,20 +41,28 @@ def _format_ts(moment: dt.datetime | None) -> str:
     return moment.astimezone().isoformat(sep=" ", timespec="seconds")
 
 
-def _author_lines(record) -> list[str]:  # noqa: ANN001 - ChangeRecord, avoid cycle
-    lines: list[str] = []
-    author = record.author
-    identifier = author.identifier if author is not None else "UNKNOWN"
-    lines.append(f"    Last modified by: {identifier}")
-    # Filesystem last-modified time (Section 12: file_timestamp); rendered
-    # in local time like the log timestamps. Resolver-provided timestamps
-    # (author.timestamp) stay authoritative and are shown as well.
-    file_ts = _format_ts(record.file_timestamp)
-    if file_ts:
-        lines.append(f"    Modified at: {file_ts}")
-    if author is not None and author.timestamp is not None:
-        lines.append(f"    Changed at: {_format_ts(author.timestamp)}")
-    return lines
+def _file_line(record: ChangeRecord, separator: str) -> str:
+    """One line per file, git --name-status style (Section 15).
+
+    Grammar:
+        A <sep> <path> <sep> <author> <sep> <mtime>   added
+        M <sep> <path> <sep> <author> <sep> <mtime>   modified
+        R <sep> <old-path> -> <new-path>              renamed (bare)
+        D <sep> <path>                                 deleted (bare)
+
+    The filesystem last-modified time (Section 12: file_timestamp) is used
+    for the time column, rendered in local time like the log timestamps.
+    Deleted and renamed entries stay bare: the file is gone (FR-013), and a
+    pure rename preserves the original mtime so a timestamp would mislead.
+    """
+    letter = _GIT_LETTER[record.change_type]
+    if record.change_type is ChangeType.RENAMED:
+        return f"{letter} {separator} {record.previous_path or record.path} -> {record.path}"
+    if record.change_type is ChangeType.DELETED:
+        return f"{letter} {separator} {record.path}"
+    author = record.author.identifier if record.author is not None else "UNKNOWN"
+    parts = [letter, record.path, author, _format_ts(record.file_timestamp)]
+    return f" {separator} ".join(parts)
 
 
 def build_commit_message(
@@ -51,6 +70,7 @@ def build_commit_message(
     run: TrackerRun,
     collected_at: dt.datetime | None = None,
     app_version: str = "1.0.0",
+    file_separator: str = ";",
 ) -> str:
     """Build the complete commit message per Sections 15/16/36."""
     counts = change_set.summary_counts()
@@ -64,23 +84,10 @@ def build_commit_message(
         lines.append(f"  {label} {counts[key]}")
     lines.append("")
 
-    for heading, records in (
-        ("Added:", change_set.added),
-        ("Modified:", change_set.modified),
-        ("Renamed:", change_set.renamed),
-        ("Deleted:", change_set.deleted),
-    ):
-        if not records:
-            continue
-        lines.append(heading)
-        for record in records:
-            if record.change_type.value == "RENAMED" and record.previous_path:
-                lines.append(f"  {record.previous_path} -> {record.path}")
-            else:
-                lines.append(f"  {record.path}")
-            if record.needs_author:
-                lines.extend(_author_lines(record))
-        lines.append("")
+    lines.append("Changes:")
+    for record in change_set.all_records():
+        lines.append(f"  {_file_line(record, file_separator)}")
+    lines.append("")
 
     # Structured trailers (Section 36)
     lines.append(f"Tracker-Version: {app_version}")

src/git_auto_tracker/config.py

@@ -90,6 +90,24 @@ class LoggingConfig:
     backup_count: int = 10
 
 
+@dataclass
+class CommitConfig:
+    """Commit-message rendering options (Sections 15 and 16)."""
+
+    #: Separator between the parts of a one-line file entry. Must not be
+    #: empty; must not occur inside paths, author identifiers or timestamps.
+    file_separator: str = ";"
+
+    @classmethod
+    def from_dict(cls, data: dict[str, Any]) -> CommitConfig:
+        separator = data.get("file_separator", ";")
+        if not isinstance(separator, str) or not separator.strip():
+            raise ConfigurationError("commit.file_separator must be a non-empty string")
+        if separator in ("\n", "\r"):
+            raise ConfigurationError("commit.file_separator must not be a line break")
+        return cls(file_separator=separator)
+
+
 @dataclass
 class AppConfig:
     repository_path: Path
@@ -101,6 +119,7 @@ class AppConfig:
     author_resolution: AuthorResolutionConfig
     logging: LoggingConfig
     timezone: str | None = None
+    commit: CommitConfig = field(default_factory=CommitConfig)
 
     @classmethod
     def from_dict(cls, data: dict[str, Any], config_dir: Path) -> AppConfig:
@@ -152,6 +171,7 @@ class AppConfig:
                     max_size_mb=int(logging_cfg.get("max_size_mb", 20)),
                     backup_count=int(logging_cfg.get("backup_count", 10)),
                 ),
+                commit=CommitConfig.from_dict(data.get("commit", {})),
                 timezone=app_cfg.get("timezone"),
             )
         except ConfigurationError: