#2209 bumped ureq to 3.x but the AgentBuilder-based webhook sender
was not ported (branch update raced the merge). ureq 3 replaces
AgentBuilder with Agent::config_builder(); timeouts are Option-wrapped
and status() returns http::StatusCode.
- add ecc2/rust-toolchain.toml pinning stable 1.96 (deps now require
edition2024, which needs rustc 1.85+; local 1.84 could no longer build)
- make git test fixtures hermetic: disable core.hooksPath inside temp
repos so global identity-checking pre-push hooks cannot fail tests