Session log: /save + /sync multi-user change summaries

Enhance /save and /sync slash commands to attribute commits by author
so Mike and Howard can see at a glance what the other person did.

- sync.sh: loads identity.json, shows incoming/outgoing commits with
  author + age before pull/push, groups by author in final summary
- sync.md: describes the new output format + conflict attribution
- save.md: pre-commit Change Summary block + post-commit Summary

Motivation: repo is now shared across team, `git log` alone made it
hard to see "when did Howard change that?" without hunting.

.claude/commands/save.md

@@ -72,9 +72,32 @@ Format credentials as:
 
 ## After Saving
 
+Before committing, emit a **Change Summary** block for the user to review:
+
+```
+## Change Summary (this session)
+User: <full_name> (from .claude/identity.json)
+Machine: <HOSTNAME>
+
+Files changed:
+<output of: git status --short>
+
+Stats:
+<output of: git diff --stat HEAD>
+```
+
+Then:
 1. Commit with message: "Session log: [brief description of work done]"
 2. Push to gitea remote (if configured)
-3. Confirm push was successful
+3. After push, emit a **Post-commit Summary**:
+   - New commit SHA + message
+   - Author (from `git log -1 --format='%an <%ae>'`)
+   - Files in the commit (from `git show --stat HEAD`)
+4. Confirm push was successful
+
+### Why the summary
+
+In the multi-user setup, commits can land in `main` from either team member. Always attributing author + files makes it obvious who made what change when someone else pulls the repo. Saves re-reading diffs to figure out "wait, when did that happen?"
 
 ## Purpose
 

.claude/commands/sync.md

@@ -7,23 +7,33 @@ bash .claude/scripts/sync.sh
 ```
 
 The script automatically:
-1. Stages and commits local changes (if any)
-2. Fetches and pulls remote changes
-3. Pushes local changes
-4. Reports sync status
+1. Stages and commits local changes (attributed to the current user from `.claude/identity.json`)
+2. Fetches remote and shows **incoming commits with authors** before pulling
+3. Shows **outgoing commits with authors** before pushing
+4. Pulls (rebase), then pushes
+5. Prints a final change summary (who committed what, on which side)
 
-After the script completes, report the 3 most recent session logs:
+## After the script completes
+
+The script emits a "Sync Summary" block. Relay the key bits to the user:
+
+- **Incoming from remote:** N commits. If N > 0, list commits as `<short-sha> <author> — <message>` so the user immediately sees what Howard / Mike / other teammates pushed since their last sync.
+- **Outgoing to remote:** M commits by the current user (this is what they're publishing).
+- **Net file changes in this sync:** output of `git diff --stat <prev-HEAD>..HEAD -- . ':(exclude)session-logs'` (or similar scoping) so the user sees the meaningful edits, not noise.
+
+Then report the 3 most recent session logs:
 ```bash
 ls -t session-logs/*.md projects/*/session-logs/*.md clients/*/session-logs/*.md 2>/dev/null | head -3
 ```
 
-## Conflict Resolution
+## Conflict resolution
 
-- **Session logs:** Keep both, rename with machine suffix
-- **credentials.md:** Do NOT auto-merge, report to user
-- **Other files:** Standard git conflict resolution
+- **Session logs:** Keep both, rename with machine suffix. Note which user authored each conflicting side.
+- **credentials.md:** Do NOT auto-merge, report to user.
+- **Other files:** Standard git conflict resolution. When presenting a conflict, include the author of the conflicting commits on each side so the user can coordinate (e.g., "Howard changed this in commit abc123 on 2026-04-15").
 
-## Error Handling
+## Error handling
 
-If push fails with auth error, retry once (transient Gitea auth issue).
-If pull fails with conflicts, report affected files and ask for guidance.
+- **Auth failure on push:** retry once (transient Gitea auth issue).
+- **Pull conflicts:** report affected files + author of each conflicting side, then ask for guidance.
+- **No identity.json yet:** follow the onboarding flow in CLAUDE.md before syncing.