Bump workspace to 0.13.0. Inter-crate path deps synced in lockstep
(16 pins across 9 crates/*/Cargo.toml, 0.12.0 -> 0.13.0). CHANGELOG
rewritten with the v0.13.0 entry.

Feature carried in this release: git_commit dotfile / dot-dir
safeguard + force_dot override (b9885cb).

Note: /bump skill Step 1 does not currently sync inter-crate path
deps; the sync was done manually here per the CHANGELOG v0.5.0
lockstep convention. Extending /bump to auto-sync path deps is a
skill-side carry.