compile_c_transcendentals.nim compiles vendor bid128_trig_moduli.c, but that file is not upstream and was never generated: update-bid listed it in ROOT_CS (so copy_root_c looked for a nonexistent upstream file) and the promised sin/cos extern patch didn't exist, so the build failed to find the file.

- Add extract_trig_moduli(): pull the shared ~12k-line bid_decimal128_moduli table out of bid128_sin.c into bid128_trig_moduli.c with external linkage, and rewrite the in-file tables in sin/cos to extern declarations so it is emitted once (QSPI-placed on firmware) instead of duplicated per TU. - Drop bid128_trig_moduli.c from ROOT_CS (not an upstream source). - Fix patch_bid_binarydecimal(): two #endif substitutions no longer matched the current upstream (blank-line + signature drift), leaving unterminated #if directives. Re-anchor all four IQ32_BID_BINARY128_ONLY guards on the banner + function name and assert a 4-open/4-close balance so future drift fails loudly instead of producing a non-compiling tree. - ensure-bid: add bid128_trig_moduli.c to the marker set so a tree vendored before these patches is regenerated rather than treated as complete. check-in: d28a7b676a user: tangent tags: trunk