JNV JEE-Advanced results absent from production fact_student_jee_advanced_results

**Problem.** For the JNV universe, `production_dbt_final.fact_student_jee_advanced_results` carries almost **no** Advanced qualifiers — JNV CoE / Nodal / PMU(NVS) read ≈ 0 `overall_qualified` across 2024-2026 — while `external_data_sources.jnv_fact_jee_results` **does** carry JEE-Advanced qualification (`jee_advanced_qualified`) for the JNV cohort in 2024 and 2025.

**Why it matters.** Any analysis reading the production Advanced flag for JNV students undercounts IIT-track outcomes to near zero. We currently route around this by unioning the NTA record from `jnv_fact_jee_results`, but the two sources disagreeing on the same students is a trap.

**Evidence.** `jnv_fact_jee_results` (Avanti-served, fk not null): 2024 = 186 Advanced qualifiers, 2025 = 327. The production Advanced table for the same JNV cohort is ~0.

**Open question for the data team.** Is production `fact_student_jee_advanced_results` simply not ingesting the JNV Advanced results, or is `jnv_fact_jee_results` the intended source of record for JNV Advanced? Either way, which table should analyses trust for JNV JEE-Advanced?

Compare production_dbt_final.fact_student_jee_advanced_results with external_data_sources.jnv_fact_jee_results for the JNV cohort in 2024 and 2025, using the reported Advanced qualification counts as the starting point. Trace whether the production table ingests these results or whether the external table is intended as the source of record, then document which table analyses should trust.

Written by the indexing model from the issue text.