docs: push summary for Parquet diagnostics

All diagnostic code already in place from previous commits:
- Enhanced write logging with footer tracking
- Parquet 1.16.0 upgrade
- File download & inspection on failure (b767825ba)

This push just adds documentation explaining what will happen
when CI runs and what the file analysis will reveal.

Ready to get definitive answer about the 78-byte discrepancy!

test/java/spark/PUSH_SUMMARY.md

@@ -0,0 +1,156 @@
+# Ready to Push - Comprehensive Diagnostics
+
+## Current Status
+
+**Branch:** `java-client-replication-configuration`  
+**Commits ahead of origin:** 1 (revert of documentation file)  
+**All diagnostic code is already in place from previous pushes**
+
+## What This Push Contains
+
+### Commit: afce69db1
+```
+Revert "docs: comprehensive analysis of persistent 78-byte Parquet issue"
+```
+
+Removes the `PARQUET_ISSUE_SUMMARY.md` documentation file (cleanup).
+
+## What's Already Pushed and Active
+
+The following diagnostic features are already in origin and will run on next CI trigger:
+
+### 1. Enhanced Write Logging (Commits: 48a2ddf, 885354b, 65c3ead)
+- Tracks every write with `totalBytesWritten` counter
+- Logs footer-related writes (marked [FOOTER?])
+- Shows write call count for pattern analysis
+
+### 2. Parquet 1.16.0 Upgrade (Commit: 12504dc1a)
+- Upgraded from 1.13.1 to 1.16.0
+- All Parquet dependencies coordinated
+- Result: Changed file sizes but error persists
+
+### 3. **File Download & Inspection (Commit: b767825ba)** ⭐
+```yaml
+- name: Download and examine Parquet files
+  if: failure()
+  working-directory: test/java/spark
+  run: |
+    # Install parquet-tools
+    pip3 install parquet-tools
+    
+    # Download failing Parquet file
+    curl -o test.parquet "http://localhost:8888/test-spark/employees/..."
+    
+    # Check magic bytes (PAR1)
+    # Hex dump header and footer  
+    # Run parquet-tools inspect/show
+    # Upload as artifact
+```
+
+This will definitively show if the file is valid!
+
+## What Will Happen After Push
+
+1. **GitHub Actions triggers automatically**
+2. **All diagnostics run** (already in place)
+3. **Test fails** (expected - 78-byte error persists)
+4. **File download step executes** (on failure)
+5. **Detailed file analysis** printed to logs:
+   - File size (should be 693 or 705 bytes)
+   - PAR1 magic bytes check (header + trailer)
+   - Hex dump of footer (last 200 bytes)
+   - parquet-tools inspection output
+6. **Artifact uploaded:** `failed-parquet-file` (test.parquet)
+
+## Expected Output from File Analysis
+
+### If File is Valid:
+```
+✓ PAR1 magic at start
+✓ PAR1 magic at end
+✓ Size: 693 bytes
+parquet-tools inspect: [metadata displayed]
+parquet-tools show: [can or cannot read data]
+```
+
+### If File is Incomplete:
+```
+✓ PAR1 magic at start
+✗ No PAR1 magic at end
+✓ Size: 693 bytes
+Footer appears truncated
+```
+
+## Key Questions This Will Answer
+
+1. **Is the file structurally complete?**
+   - Has PAR1 header? ✓ or ✗
+   - Has PAR1 trailer? ✓ or ✗
+
+2. **Can standard Parquet tools read it?**
+   - If YES: Spark/SeaweedFS integration issue
+   - If NO with same error: Footer metadata wrong
+   - If NO with different error: New clue
+
+3. **What does the footer actually contain?**
+   - Hex dump will show raw footer bytes
+   - Can manually decode to see column offsets
+
+4. **Where should we focus next?**
+   - File format (if incomplete)
+   - Parquet writer bug (if wrong metadata)
+   - SeaweedFS read path (if file is valid)
+   - Spark integration (if tools can read it)
+
+## Artifacts Available After Run
+
+1. **Test results:** `spark-test-results` (surefire reports)
+2. **Parquet file:** `failed-parquet-file` (test.parquet)
+   - Download and analyze locally
+   - Use parquet-tools, pyarrow, or hex editor
+
+## Commands to Push
+
+```bash
+# Simple push (recommended)
+git push origin java-client-replication-configuration
+
+# Or with verbose output
+git push -v origin java-client-replication-configuration
+
+# To force push (NOT NEEDED - history is clean)
+# git push --force origin java-client-replication-configuration
+```
+
+## After CI Completes
+
+1. **Check Actions tab** for workflow run
+2. **Look for "Download and examine Parquet files"** step
+3. **Read the output** to see file analysis
+4. **Download `failed-parquet-file` artifact** for local inspection
+5. **Based on results**, proceed with:
+   - Option A: Fix Parquet footer generation
+   - Option B: Try uncompressed Parquet
+   - Option C: Investigate SeaweedFS read path
+   - Option D: Update Spark/Parquet version
+
+## Current Understanding
+
+From logs, we know:
+- ✅ All 693 bytes are written
+- ✅ Footer trailer is written (last 6 bytes)
+- ✅ Buffer is fully flushed
+- ✅ File metadata shows 693 bytes
+- ❌ Parquet reader expects 771 bytes (693 + 78)
+- ❌ Consistent 78-byte discrepancy across all files
+
+**Next step after download:** See if the 78 bytes are actually missing, or if footer just claims they should exist.
+
+## Timeline
+
+- Push now → ~2 minutes
+- CI starts → ~30 seconds  
+- Build & test → ~5-10 minutes
+- Test fails → File download executes
+- Results available → ~15 minutes total
+