feat: Phase 4 - End Node Template Engine (v0.9n)

Backend:
- workflow_models.py: EndNodeOutputMode enum (AUTO, TEMPLATE)
- workflow_executor.py: execute_end_node() with Jinja2 rendering
- Template Context: {{node_id.analysis_core}}, {{node_id.decision_signals.key}}
- Conditional Rendering: {% if node_id %} for optional paths
- AUTO Mode: Backward compatible (concatenates all analyses)
- TEMPLATE Mode: Custom Jinja2 templates with placeholders

Features:
- Access node results: {{node_id.analysis_core}}
- Access signals: {{node_id.decision_signals.relevanz}}
- Optional paths: {% if node_id %}...{% endif %}
- Default values: {{node_id|default("N/A")}}

Version: 0.9n
Module: workflow 0.6.0
Konzept: konzept_workflow_engine_konsolidated.md (Section 11)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/version.py

@@ -7,8 +7,8 @@ Semantic Versioning: MAJOR.MINOR.PATCH
 - PATCH: Bugfix, kleine Änderung, Refactor
 """
 
-APP_VERSION = "0.9m"
-BUILD_DATE = "2026-04-04"
+APP_VERSION = "0.9n"
+BUILD_DATE = "2026-04-05"
 DB_SCHEMA_VERSION = "20260403"  # Migration 034
 
 MODULE_VERSIONS = {
@@ -27,10 +27,23 @@ MODULE_VERSIONS = {
     "exportdata": "1.1.0",
     "importdata": "1.0.0",
     "membership": "2.1.0",
-    "workflow": "0.5.0",  # Phase 4: Join Nodes + Path Consolidation
+    "workflow": "0.6.0",  # Phase 4: End Node Template Engine
 }
 
 CHANGELOG = [
+    {
+        "version": "0.9n",
+        "date": "2026-04-05",
+        "changes": [
+            "Phase 4: End Node Template Engine",
+            "workflow_models.py: EndNodeOutputMode enum (AUTO, TEMPLATE)",
+            "workflow_executor.py: execute_end_node() with Jinja2 template rendering",
+            "Template Context: {{node_id.analysis_core}}, {{node_id.decision_signals.key}}",
+            "Conditional Rendering: {% if node_id %} for optional paths",
+            "AUTO Mode: Backward compatible concatenation of all analyses",
+            "TEMPLATE Mode: Custom Jinja2 templates with placeholder support",
+        ]
+    },
     {
         "version": "0.9m",
         "date": "2026-04-04",

backend/workflow_executor.py

@@ -15,10 +15,12 @@ from datetime import datetime
 import uuid
 import logging
 import json
+from jinja2 import Template, TemplateError
 
 from workflow_models import (
     WorkflowGraph, NodeExecutionState, ExecutionResult,
-    NodeStatus, NormalizedSignal, FallbackStrategy, SignalStatus
+    NodeStatus, NormalizedSignal, FallbackStrategy, SignalStatus,
+    EndNodeOutputMode
 )
 from workflow_engine import parse_workflow_graph, get_execution_order
 from question_augmenter import (
@@ -251,9 +253,9 @@ async def execute_node(
     started_at = datetime.utcnow().isoformat()
 
     try:
-        # Start/End Nodes: No-Op
-        if node.type in ["start", "end"]:
-            logger.debug(f"Node {node.id}: No-op ({node.type})")
+        # Start Node: No-Op
+        if node.type == "start":
+            logger.debug(f"Node {node.id}: No-op (start)")
             return NodeExecutionState(
                 node_id=node.id,
                 status=NodeStatus.EXECUTED,
@@ -261,6 +263,10 @@ async def execute_node(
                 completed_at=datetime.utcnow().isoformat()
             )
 
+        # End Node: Output Generation (Phase 4)
+        if node.type == "end":
+            return execute_end_node(node, context)
+
         # Logic Nodes (Phase 3)
         if node.type == "logic":
             return execute_logic_node(node, context, graph)
@@ -515,6 +521,128 @@ def execute_join_node(
         )
 
 
+def execute_end_node(
+    node,
+    context: Dict[str, Any]
+) -> NodeExecutionState:
+    """
+    Führt End Node aus (Phase 4 - Template Engine).
+
+    Args:
+        node: WorkflowNode vom Typ "end"
+        context: Execution context mit node_results
+
+    Returns:
+        NodeExecutionState mit finaler Ausgabe in analysis_core
+
+    Output Modes:
+        - AUTO: Concatenates all analysis_core values (backward compatible)
+        - TEMPLATE: Renders Jinja2 template with {{node_id.property}} placeholders
+
+    Template Context:
+        - {{node_id.analysis_core}}: Analysis text from node
+        - {{node_id.decision_signals}}: Dict of raw decision signals
+        - {{node_id.decision_signals.key}}: Specific signal value
+        - {{node_id.status}}: Node execution status
+        - Conditional rendering: {% if node_id %}...{% endif %}
+        - Default values: {{node_id|default("fallback")}}
+
+    Example Template:
+        ```
+        # Final Analysis
+
+        ## Body Composition
+        {{body_analysis.analysis_core}}
+
+        {% if training_analysis %}
+        ## Training Recommendation
+        {{training_analysis.analysis_core}}
+        {% endif %}
+
+        ## Decision Factors
+        - Relevance: {{body_analysis.decision_signals.relevanz}}
+        - Priority: {{body_analysis.decision_signals.prioritaet}}
+        ```
+    """
+    started_at = datetime.utcnow().isoformat()
+
+    try:
+        logger.info(f"Executing end node: {node.id}")
+
+        # Determine output mode (default: AUTO for backward compatibility)
+        output_mode = node.output_mode or EndNodeOutputMode.AUTO
+
+        if output_mode == EndNodeOutputMode.AUTO:
+            # AUTO mode: Concatenate all analysis_core values
+            logger.debug(f"End node {node.id}: Using AUTO output mode")
+
+            combined_analysis = []
+            for node_id, node_state in context.get("node_results", {}).items():
+                if node_state.status == NodeStatus.EXECUTED and node_state.analysis_core:
+                    combined_analysis.append(f"## {node_id}\n{node_state.analysis_core}")
+
+            final_output = "\n\n".join(combined_analysis) if combined_analysis else "[No analysis generated]"
+
+        elif output_mode == EndNodeOutputMode.TEMPLATE:
+            # TEMPLATE mode: Render Jinja2 template
+            logger.debug(f"End node {node.id}: Using TEMPLATE output mode")
+
+            if not node.template:
+                raise ValueError(f"End node {node.id} has output_mode=TEMPLATE but no template defined")
+
+            # Build template context: {{node_id}} → {analysis_core, decision_signals, status}
+            template_context = {}
+            for node_id, node_state in context.get("node_results", {}).items():
+                template_context[node_id] = {
+                    "analysis_core": node_state.analysis_core or "",
+                    "decision_signals": node_state.decision_signals or {},
+                    "reasoning_anchors": node_state.reasoning_anchors or "",
+                    "status": node_state.status.value if node_state.status else "unknown",
+                    # Add individual signal access: {{node_id.signal_name}}
+                    **node_state.decision_signals  # Flatten signals into node context
+                }
+
+            logger.debug(f"End node {node.id}: Built template context for {len(template_context)} nodes")
+
+            # Render template
+            try:
+                jinja_template = Template(node.template)
+                final_output = jinja_template.render(template_context)
+                logger.info(f"End node {node.id}: Template rendered successfully ({len(final_output)} chars)")
+            except TemplateError as te:
+                error_msg = f"Template rendering failed: {str(te)}"
+                logger.error(f"End node {node.id}: {error_msg}")
+                return NodeExecutionState(
+                    node_id=node.id,
+                    status=NodeStatus.FAILED,
+                    error=error_msg,
+                    started_at=started_at,
+                    completed_at=datetime.utcnow().isoformat()
+                )
+
+        else:
+            raise ValueError(f"Unknown output_mode: {output_mode}")
+
+        # Return NodeExecutionState with final output
+        return NodeExecutionState(
+            node_id=node.id,
+            status=NodeStatus.EXECUTED,
+            analysis_core=final_output,
+            started_at=started_at,
+            completed_at=datetime.utcnow().isoformat()
+        )
+
+    except Exception as e:
+        logger.error(f"End node execution failed ({node.id}): {e}", exc_info=True)
+        return NodeExecutionState(
+            node_id=node.id,
+            status=NodeStatus.FAILED,
+            error=str(e),
+            started_at=started_at,
+            completed_at=datetime.utcnow().isoformat()
+        )
+
+
 def _apply_fallback(
     node,
     graph: WorkflowGraph,

backend/workflow_models.py

@@ -79,6 +79,12 @@ class LogicOperator(str, Enum):
     NOT = "not"
 
 
+class EndNodeOutputMode(str, Enum):
+    """Output-Modi für End Node (Phase 4)"""
+    AUTO = "auto"            # Automatisch: Concatenate all analyses
+    TEMPLATE = "template"    # Custom Jinja2 template
+
+
 # ── Hilfsmodelle ──────────────────────────────────────────────────────────────
 
 class Position(BaseModel):
@@ -191,9 +197,15 @@ class WorkflowNode(BaseModel):
     condition: Optional[Condition] = Field(None, description="Bedingung für Pfad-Routing")
     fallback: Optional[FallbackConfig] = Field(None, description="Fallback-Konfiguration")
 
-    # JOIN-Knoten
+    # JOIN-Knoten (Phase 4)
     join_strategy: Optional[JoinStrategy] = Field(None, description="Join-Strategie")
     skip_handling: Optional[SkipHandling] = Field(None, description="Umgang mit übersprungenen Pfaden")
+    min_paths: Optional[int] = Field(None, description="Mindestanzahl erforderlicher Pfade (für REQUIRE_MINIMUM)")
+    timeout_seconds: Optional[int] = Field(None, description="Timeout für BEST_EFFORT-Strategie")
+
+    # END-Knoten (Phase 4)
+    output_mode: Optional[EndNodeOutputMode] = Field(None, description="Output-Modus: auto oder template")
+    template: Optional[str] = Field(None, description="Jinja2 template für finales Ergebnis (wenn output_mode=template)")
 
 
 class WorkflowEdge(BaseModel):