feat: Add Streamlit dashboard with Blueprint compliance (v2.1.0)

Dashboard Features:
- 8 navigation sections: Overview, Outcomes, Poor CX, FCR, Churn, Agent, Call Explorer, Export
- Beyond Brand Identity styling (colors #6D84E3, Outfit font)
- RCA Sankey diagram (Driver → Outcome → Churn Risk flow)
- Correlation heatmaps (driver co-occurrence, driver-outcome)
- Outcome Deep Dive (root causes, correlation, duration analysis)
- Export functionality (Excel, HTML, JSON)

Blueprint Compliance:
- FCR: 4 categories (Primera Llamada/Rellamada × Sin/Con Riesgo de Fuga)
- Churn: Binary view (Sin Riesgo de Fuga / En Riesgo de Fuga)
- Agent: Talento Para Replicar / Oportunidades de Mejora
- Fixed FCR rate calculation (only FIRST_CALL counts as success)

Technical:
- Streamlit + Plotly for interactive visualizations
- Light theme configuration (.streamlit/config.toml)
- Fixed Plotly colorbar titlefont deprecation

Documentation:
- Updated PROJECT_CONTEXT.md, TODO.md, CHANGELOG.md
- Added 4 new technical decisions (TD-014 to TD-017)
- Created TROUBLESHOOTING.md with 10 common issues

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/pipeline/__init__.py

@@ -0,0 +1,29 @@
+"""
+CXInsights - Pipeline Module
+
+End-to-end pipeline for call analysis.
+"""
+
+from src.pipeline.models import (
+    PipelineConfig,
+    PipelineManifest,
+    PipelineStage,
+    StageManifest,
+    StageStatus,
+)
+from src.pipeline.pipeline import (
+    CXInsightsPipeline,
+    run_pipeline,
+)
+
+__all__ = [
+    # Models
+    "PipelineConfig",
+    "PipelineManifest",
+    "PipelineStage",
+    "StageManifest",
+    "StageStatus",
+    # Pipeline
+    "CXInsightsPipeline",
+    "run_pipeline",
+]