feat: BOM auto-extraction and manifest field population (#276, #277)

Documentation updates:
- KNOWN_ISSUES.md: correct #6 (datum handling), resolve #10
  (delete_bom_entry) and #11 (silo icons), fix stale formatDate
  reference, mark completed next steps, add new next steps.
- INTEGRATION_PLAN.md: correct ztools SDK migration claim.

kc_format.py (#277):
- New _manifest_enrich_hook: populates part_uuid from SiloItemId and
  silo_instance from Silo API URL on every .kc save.
- New update_manifest_fields(): public API to update manifest fields
  in an already-saved .kc ZIP (used for post-upload revision_hash).

mods/silo submodule (#276):
- New bom_sync.py extraction engine.
- Post-commit hooks for BOM sync and manifest revision update.
- SSE bom_merged signal + Activity pane handler.
- merge_bom_json client method (forward-looking).

Refs: #276, #277

src/Mod/Create/kc_format.py

@@ -45,6 +45,51 @@ def _metadata_save_hook(doc, filename, entries):
 register_pre_reinject(_metadata_save_hook)
 
 
+def _manifest_enrich_hook(doc, filename, entries):
+    """Populate silo_instance and part_uuid from the tracked Silo object."""
+    raw = entries.get("silo/manifest.json")
+    if raw is None:
+        return
+    try:
+        manifest = json.loads(raw)
+    except (json.JSONDecodeError, ValueError):
+        return
+
+    changed = False
+
+    # Populate part_uuid from SiloItemId if available.
+    for obj in doc.Objects:
+        if hasattr(obj, "SiloItemId") and obj.SiloItemId:
+            if manifest.get("part_uuid") != obj.SiloItemId:
+                manifest["part_uuid"] = obj.SiloItemId
+                changed = True
+            break
+
+    # Populate silo_instance from Silo settings.
+    if not manifest.get("silo_instance"):
+        try:
+            import silo_commands
+
+            api_url = silo_commands._get_api_url()
+            if api_url:
+                # Strip /api suffix to get base instance URL.
+                instance = api_url.rstrip("/")
+                if instance.endswith("/api"):
+                    instance = instance[:-4]
+                manifest["silo_instance"] = instance
+                changed = True
+        except Exception:
+            pass
+
+    if changed:
+        entries["silo/manifest.json"] = (json.dumps(manifest, indent=2) + "\n").encode(
+            "utf-8"
+        )
+
+
+register_pre_reinject(_manifest_enrich_hook)
+
+
 KC_VERSION = "1.0"
 
 
@@ -133,6 +178,34 @@ class _KcFormatObserver:
             )
 
 
+def update_manifest_fields(filename, updates):
+    """Update fields in an existing .kc manifest after save.
+
+    *filename*: path to the .kc file.
+    *updates*: dict of field_name -> value to merge into the manifest.
+
+    Used by silo_commands to write ``revision_hash`` after a successful
+    upload (which happens after the ZIP has already been written by save).
+    """
+    if not filename or not filename.lower().endswith(".kc"):
+        return
+    if not os.path.isfile(filename):
+        return
+    try:
+        with zipfile.ZipFile(filename, "a") as zf:
+            if "silo/manifest.json" not in zf.namelist():
+                return
+            raw = zf.read("silo/manifest.json")
+            manifest = json.loads(raw)
+            manifest.update(updates)
+            zf.writestr(
+                "silo/manifest.json",
+                json.dumps(manifest, indent=2) + "\n",
+            )
+    except Exception as e:
+        FreeCAD.Console.PrintWarning(f"kc_format: failed to update manifest: {e}\n")
+
+
 def register():
     """Connect to application-level save signals."""
     FreeCAD.addDocumentObserver(_KcFormatObserver())