nx_teacher_merge.nx

nx_teacher_merge.nx -- MULTI-SOURCE synthesis into ONE unified Nishi Teacher capability store (Teacher arc, rung R2b). Extends nx_teacher_synthesize (DRY -- reuses tsyn_field/streq/store_has_rule/ recall) so the team can "consume ALL our information" from a single native store, not many raw TSVs. Operator doctrine [[feedback-synthesize-before-retire]]: synthesize each information-bearing ledger's insight into the team's living capability store; once absorbed the raw is redundant. This rung makes the store MULTI-SOURCE + heterogeneous-schema + de-duplicated: tsyn_merge_cols(src, source_tag, prefix, id_col, rule_col) -> rows ADDED (-1 read, -2 commit) appends the ledger's insights at the store's CURRENT count offset (so a 2nd source never clobbers the 1st -- seg_store append-segment + last-wins count), reading the id + the insight from the caller-specified columns (so build_learnings 0/2, landmines 0/2, nishi_cardinals 0/1 all map in), and SKIPS any rule already in the store (cross-source dedup -> idempotent re-merge). tsyn_redundant_col(src, prefix, rule_col) -> 1 iff every insight of src is recoverable from the store. Faithful extraction only -- no fabricated insight (Rule 4). No hardware writes / network (Rule 26). license_tier: ORIGINAL