Implement Dashboard consolidation + Performance logging

Features:
- Add unified "Dashboard Complet" sheet (Excel) with all 9 sections
- Add unified "Dashboard Complet" page (PDF) with key metrics
- Fix VALOARE_ANTERIOARA NULL bug (use sumar_executiv_yoy directly)
- Add PerformanceLogger class for timing analysis
- Remove redundant consolidated sheets (keep only Dashboard Complet)

Bug fixes:
- Fix Excel formula error (=== interpreted as formula, changed to >>>)
- Fix args.output → args.output_dir in perf.summary()

Performance analysis:
- Add PERFORMANCE_ANALYSIS.md with detailed breakdown
- SQL queries take 94% of runtime (31 min), Excel/PDF only 1%
- Identified slow queries for optimization

Documentation:
- Update CLAUDE.md with new structure
- Add context handover for query optimization task

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

queries.py

@@ -2075,7 +2075,8 @@ ranked_anterior AS (
     SELECT vanzari, ROW_NUMBER() OVER (ORDER BY vanzari DESC) AS rn
     FROM vanzari_anterior
 ),
-metrics_anterior AS (
+-- Raw metrics for anterior (may have NULL if no data)
+metrics_anterior_raw AS (
     SELECT
         SUM(vanzari) AS total,
         SUM(CASE WHEN rn <= 1 THEN vanzari ELSE 0 END) AS top1,
@@ -2083,15 +2084,25 @@ metrics_anterior AS (
         SUM(CASE WHEN rn <= 10 THEN vanzari ELSE 0 END) AS top10
     FROM ranked_anterior
 ),
+-- Fallback to 0 for NULL values (when no anterior data exists)
+metrics_anterior AS (
+    SELECT
+        NVL(total, 0) AS total,
+        NVL(top1, 0) AS top1,
+        NVL(top5, 0) AS top5,
+        NVL(top10, 0) AS top10
+    FROM metrics_anterior_raw
+),
 -- Final metrics: just 1 row each, no cartesian product
 combined AS (
     SELECT
         ROUND(mc.top1 * 100.0 / NULLIF(mc.total, 0), 2) AS pct_curent_1,
-        ROUND(ma.top1 * 100.0 / NULLIF(ma.total, 0), 2) AS pct_anterior_1,
+        CASE WHEN ma.total = 0 THEN NULL ELSE ROUND(ma.top1 * 100.0 / ma.total, 2) END AS pct_anterior_1,
         ROUND(mc.top5 * 100.0 / NULLIF(mc.total, 0), 2) AS pct_curent_5,
-        ROUND(ma.top5 * 100.0 / NULLIF(ma.total, 0), 2) AS pct_anterior_5,
+        CASE WHEN ma.total = 0 THEN NULL ELSE ROUND(ma.top5 * 100.0 / ma.total, 2) END AS pct_anterior_5,
         ROUND(mc.top10 * 100.0 / NULLIF(mc.total, 0), 2) AS pct_curent_10,
-        ROUND(ma.top10 * 100.0 / NULLIF(ma.total, 0), 2) AS pct_anterior_10
+        CASE WHEN ma.total = 0 THEN NULL ELSE ROUND(ma.top10 * 100.0 / ma.total, 2) END AS pct_anterior_10,
+        CASE WHEN ma.total > 0 THEN 1 ELSE 0 END AS has_anterior
     FROM metrics_curent mc
     CROSS JOIN metrics_anterior ma
 )
@@ -2099,8 +2110,9 @@ SELECT
     'Top 1 client' AS indicator,
     pct_curent_1 AS procent_curent,
     pct_anterior_1 AS procent_anterior,
-    ROUND(pct_curent_1 - pct_anterior_1, 2) AS variatie,
+    CASE WHEN has_anterior = 1 THEN ROUND(pct_curent_1 - pct_anterior_1, 2) ELSE NULL END AS variatie,
     CASE
+        WHEN has_anterior = 0 THEN 'FARA DATE YOY'
         WHEN pct_curent_1 < pct_anterior_1 THEN 'DIVERSIFICARE'
         WHEN pct_curent_1 > pct_anterior_1 + 5 THEN 'CONCENTRARE'
         ELSE 'STABIL'
@@ -2111,8 +2123,9 @@ SELECT
     'Top 5 clienti' AS indicator,
     pct_curent_5 AS procent_curent,
     pct_anterior_5 AS procent_anterior,
-    ROUND(pct_curent_5 - pct_anterior_5, 2) AS variatie,
+    CASE WHEN has_anterior = 1 THEN ROUND(pct_curent_5 - pct_anterior_5, 2) ELSE NULL END AS variatie,
     CASE
+        WHEN has_anterior = 0 THEN 'FARA DATE YOY'
         WHEN pct_curent_5 < pct_anterior_5 THEN 'DIVERSIFICARE'
         WHEN pct_curent_5 > pct_anterior_5 + 5 THEN 'CONCENTRARE'
         ELSE 'STABIL'
@@ -2123,8 +2136,9 @@ SELECT
     'Top 10 clienti' AS indicator,
     pct_curent_10 AS procent_curent,
     pct_anterior_10 AS procent_anterior,
-    ROUND(pct_curent_10 - pct_anterior_10, 2) AS variatie,
+    CASE WHEN has_anterior = 1 THEN ROUND(pct_curent_10 - pct_anterior_10, 2) ELSE NULL END AS variatie,
     CASE
+        WHEN has_anterior = 0 THEN 'FARA DATE YOY'
         WHEN pct_curent_10 < pct_anterior_10 THEN 'DIVERSIFICARE'
         WHEN pct_curent_10 > pct_anterior_10 + 5 THEN 'CONCENTRARE'
         ELSE 'STABIL'