feat: nightly Tracy trace capture for chonk tx with real inputs

[AztecBot]

Summary

Adds a nightly CI job that builds bb with Tracy profiling enabled, runs a chonk prove with real IVC inputs, captures a Tracy trace, and uploads it to S3 for later analysis.

This gives the team automatic, up-to-date Tracy traces to investigate thread scheduling, memory allocation patterns, and performance regressions without manual setup.

How it works

1. Builds bb with a Tracy preset (default: tracy-time-instrumented)
2. Builds tracy-capture headless tool from the same Tracy source CMake already downloads
3. Downloads real IVC inputs from S3 (same pinned inputs used by VK stability tests)
4. Runs bb prove --scheme chonk with real inputs while tracy-capture records the trace
5. Uploads the compressed trace to s3://aztec-ci-artifacts/protocol/tracy-traces/

Traces can be downloaded and viewed locally:

aws s3 cp s3://aztec-ci-artifacts/protocol/tracy-traces/chonk-tracy-time-instrumented-20260408-abc1234.utrace.zst .
zstd -d *.zst
tracy *.utrace

Files

• barretenberg/cpp/scripts/ci_tracy_chonk_trace.sh — main capture script
• bootstrap.sh — new ci-barretenberg-tracy-trace target
• ci.sh — new barretenberg-tracy-trace CI mode (192 CPUs, nightly dashboard)
• .github-new/workflows/nightly-tracy-trace.yml — proposed workflow (needs to be moved to .github/ by someone with CI write access)

Configurable presets

The workflow supports all four Tracy presets via workflow_dispatch:

• tracy-time-instrumented (default) — instrumented time zones
• tracy-memory — memory allocation + time instrumentation
• tracy-time-sampled — sampling-based time profiling
• tracy-gates — circuit gate count tracking

ClaudeBox log: https://claudebox.work/s/92025c94ba91f5ab?run=2