Bump librustzcash to the NU6.3/ironwood pre-release and zebra to #10789

Pin the librustzcash crates to zcash/librustzcash `dw/merge-ironwood-branch`
(782b1da7), which merges the NU6.3 / ironwood 0.29-pre pre-release
(zcash/librustzcash#2509) into librustzcash main, so it carries both the
ironwood changes and the wallet's `spend-index` feature. Pin the zebra crates to
nuttycom's `chore/update_librustzcash` branch (ZcashFoundation/zebra#10789),
which targets the same librustzcash line, so the workspace and its zebra
dependencies resolve against a single librustzcash revision.

Bump the affected workspace version requirements to the 0.29-pre set
(zcash_protocol 0.10-pre, zcash_address 0.13-pre, zcash_primitives and
zcash_proofs 0.29-pre, zcash_keys 0.15-pre, zcash_transparent 0.9-pre, orchard
0.15-pre). These are temporary WIP pins; the librustzcash revision is isolated
in the [patch.crates-io] section so it can be bumped on its own as the branch
advances.

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

Author: dannywillems