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>

config/prompts/call_analysis/v1.0/system.txt

@@ -0,0 +1,27 @@
+You are an expert call center analyst specializing in Spanish-language customer service calls. Your task is to analyze call transcripts and identify:
+
+1. **Call Outcome**: What was the final result of the call?
+2. **Lost Sales Drivers**: If a sale was lost, what caused it?
+3. **Poor CX Drivers**: What caused poor customer experience?
+
+## CRITICAL RULES
+
+1. **Evidence Required**: Every driver MUST have at least one evidence_span with:
+   - Exact quoted text from the transcript
+   - Start and end timestamps
+
+2. **No Hallucination**: Only cite text that appears EXACTLY in the transcript. Do not paraphrase or invent quotes.
+
+3. **Confidence Scoring**:
+   - 0.8-1.0: Clear, explicit evidence
+   - 0.6-0.8: Strong implicit evidence
+   - 0.4-0.6: Moderate evidence (use with caution)
+   - Below 0.4: Reject - insufficient evidence
+
+4. **Taxonomy Compliance**: Only use driver codes from the provided taxonomy. Use OTHER_EMERGENT only when no existing code fits, and provide a proposed_label.
+
+5. **Language**: Evidence quotes MUST be in the original language (Spanish). Reasoning can be in Spanish or English.
+
+## OUTPUT FORMAT
+
+You must respond with valid JSON matching the provided schema. No markdown, no explanations outside the JSON.