docs: update CHANGELOG and README for Phase 3 features

Add documentation for new rebase features:
- Progress reporting during chain rebase
- Summary report after rebase completion
- --status flag for viewing in-progress rebase state
- --cleanup-backups flag for deleting backup branches
- New integration tests

Update README with flag descriptions, usage examples, and a new
"Progress Reporting and Summary" section with sample output.

Author: dashed

CHANGELOG.md

@@ -8,6 +8,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Changed
+- Rebase now shows progress reporting during chain rebase: `📌 [2/5] Rebasing feature-auth onto main...`
+- Rebase completion now shows a summary report with counts by category (rebased, skipped, squash-reset)
+- `rebase --continue` and `rebase --skip` now show progress reporting and summary report
 - Rebase conflict error message now shows numbered recovery steps with `--continue` and `--abort` instructions
 - Replaced `process::exit(1)` with proper error propagation in core operations
   - `rebase`, `backup`, `push`, `prune`, and `pr` operations now return `Result<(), Error>` instead of calling `process::exit(1)`
@@ -62,6 +65,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - `rebase_squashed_merge_skip`, `rebase_squashed_merge_force_rebase`
 - Added `lint` Makefile target (combines `fmt-check` + `clippy-strict`)
 - Added `test-file` Makefile target for running all tests in a specific file
+- Added `--status` flag to `rebase` command to show current chain rebase state
+  - Displays per-branch status with emoji indicators (Completed, Skipped, Pending, Conflict, etc.)
+  - Shows progress through the chain and original branch information
+  - Reports "No chain rebase in progress" when no state file exists
+- Added `--cleanup-backups` flag to `rebase` command for deleting backup branches after successful rebase
+  - Works with `rebase`, `rebase --continue`, and `rebase --skip`
+  - Deletes `backup-<chain>/<branch>` branches created during squash-merge reset
+  - Reports count of cleaned up backup branches
+- Added integration tests for Phase 3 polish and UX features:
+  - `rebase_progress_reporting`, `rebase_status_no_state`, `rebase_status_during_conflict`
+  - `rebase_cleanup_backups`, `rebase_no_cleanup_without_flag`, `rebase_summary_report_with_skipped_branches`
 - Added integration tests for error propagation:
   - `rebase_nonexistent_chain`, `rebase_dirty_working_directory`, `rebase_missing_branch_in_chain`
   - `backup_nonexistent_chain`, `push_nonexistent_chain`, `prune_nonexistent_chain`

README.md

@@ -118,6 +118,18 @@ Git Chain's rebase command offers customization through its flags:
   ```
   Rolls back the entire chain rebase by restoring all branches to their original positions before the rebase started. Aborts any in-progress git rebase and cleans up the state file.
 
+- **`--status`**: Show the current chain rebase state
+  ```
+  git chain rebase --status
+  ```
+  Displays the status of each branch in an ongoing chain rebase, including which branches have been completed, skipped, or are still pending. Reports "No chain rebase in progress" when no state file exists.
+
+- **`--cleanup-backups`**: Delete backup branches after successful rebase
+  ```
+  git chain rebase --cleanup-backups
+  ```
+  After a successful rebase, automatically deletes any `backup-<chain>/<branch>` branches that were created during squash-merge reset. Can also be combined with `--continue` and `--skip`.
+
 - **`--squashed-merge=<mode>`**: How to handle branches detected as squash-merged
   ```
   git chain rebase --squashed-merge=reset   # Default: auto-backup + reset to parent
@@ -260,6 +272,40 @@ Rebasing branch feature/profiles onto feature/auth...
 # Continues with remaining branches
 ```
 
+### Progress Reporting and Summary
+
+When rebasing a chain, git-chain provides real-time progress and a summary report:
+
+**During rebase**:
+```
+📌 [1/3] Rebasing feature-auth onto master...
+📌 [2/3] Rebasing feature-profiles onto feature-auth...
+📌 [3/3] Rebasing feature-settings onto feature-profiles...
+```
+
+**After completion**:
+```
+📊 Rebase Summary for Chain: my-feature
+  ✅ Rebased: 3
+
+🎉 Successfully rebased chain my-feature
+```
+
+**Checking rebase status** during a conflict:
+```
+$ git chain rebase --status
+
+📊 Chain Rebase Status: my-feature
+   Root: master
+
+   ✅ feature-auth (1/3) onto master — Completed
+   ❌ feature-profiles (2/3) onto feature-auth — Conflict  ← current
+   ⏳ feature-settings (3/3) onto feature-profiles — Pending
+
+   Progress: 1/3 branches completed
+   Original branch: feature-settings
+```
+
 ### Recovery Options
 
 If a rebase goes wrong, Git Chain provides several recovery options:
@@ -677,6 +723,12 @@ git chain rebase --step
 # Skip rebasing the first branch onto the root branch
 git chain rebase --ignore-root
 
+# Show the status of an in-progress chain rebase
+git chain rebase --status
+
+# Delete backup branches after successful rebase
+git chain rebase --cleanup-backups
+
 # Specify how to handle squash-merged branches during rebase
 git chain rebase --squashed-merge=reset   # Auto-backup + reset (default)
 git chain rebase --squashed-merge=skip    # Skip squash-merged branches