Frosty toolkit build 2

Second build of the Battlefront II mod compiler (FrostyCli, linux-x64), used by the plugin's Step 1. Changes from build 1, all found chasing replaced character models rendering as shattered geometry:

• The manifest's streaming-chunk entries now cover the full written blob rather than the firstMip sub-range, matching the vanilla game and Frosty v1. Sub-ranged entries made every replaced mesh stream a fragment of itself.
• ShaderBlockDepot merge handler ported from Frosty v1 (hash 0x89EF2205). Mesh mods ship shader-block deltas that must be merged into the game's depot; with no handler they were silently skipped, leaving the game's original shader blocks describing a mesh that was no longer there.
• Handler output is exempt from the base-data copy skip, so merged resources actually reach the cas archives.
• ZSTD_compress P/Invoke binding gained its missing fifth argument (compression level); it was passing register garbage before.

Verified against real Frosty v1 output for the same mod: every res and chunk in the touched bundles is byte-identical decompressed (27 res including both merged shader depots), and the full read-back validation passes: res ok=84130 bad=0, chunks ok=211705 bad=0.