Calcul tranzit: coeficient distanta rotunjit la 3 zecimale + protectie impartire la 0

Pentru distante scurte (ex. 0.2 km) coeficientul de distanta rotunjit la 2
zecimale iesea 0, deci valoarea facturata era 0. Rotunjire la 3 zecimale in
do_executa si in afisarea "mod de calcul". Protectie la impartirea cu 0 la
valoarea finala cand valoarea convoiului calculat este 0.

Adauga docs/fluxuri_calcul_facturare.md (lant facturare end-to-end pe tipuri)
si referinta in CLAUDE.md. Changelog 2.0.5.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -120,6 +120,12 @@ throughout the codebase:
   the `crsFactura` structure, the VAT formulas, and which files to touch for a given task. Key
   rule: `PACK_FACTURARE.pck` is the source of truth; the `frm_factura` preview must mirror its
   formulas, and reports/list only read package-computed values.
+- **`docs/fluxuri_calcul_facturare.md`** — the end-to-end billing chain (Import → Calcul →
+  Salvare → Listare) documented per service type (tranzit, cheiaj, chirii, penalități, apă,
+  diverse): where source data is imported from (RORIS/`ips_*`), the exact value/coefficient
+  formulas and roundings, where results are persisted, and what reports/recapitulations read
+  back. Read this to find which file:line computes a given value. Includes a "Capcane cunoscute"
+  section (e.g. the distance-coefficient rounding that zeroes sub-32m distances).
 - **`Programe/proceduri_acnpro_rapoarte.prg`** — report-generation procedures feeding the
   `Rapoarte/*.frx` layouts (factura, recapitulatie_cheiaj/tranzit/penalitati, registru tranzit).
 - **`Programe/importroris*.prg`** + `importroris.pjx` — a *separate* small executable