Cold-build timing baseline -- Stage A (Gitea #1910)

D7 gate denominator. The full cargo --timings HTML (baseline-stageA.html, ~850 KB) is a generated, regenerable artefact ignored by the repo's *.html rule; the headline figures are recorded here so the gate has a tracked reference.

Run

Command: cargo clean && cargo build --workspace --timings --release
State: post-Stage-A (manifest cycle broken, terraphim_lsp revived) on branch task/1910-stage-a-cycle-break-lsp.
Host: developer macOS (Apple Silicon). Single run.
Wall time: 3m 32s (Finished release profile in 3m 32s).
Compilation units: 1048.

Note: this is a single run on a dev Mac with a warm ~/.cargo registry cache (only target/ was cleaned). The authoritative D7 denominator is a median-of-3 cold build on the bigbox self-hosted runner, to be captured in CI (sentrux-quality-gate.yml / performance-benchmarking.yml). Use this figure only as a local sanity reference, not the gate baseline.

Top 15 slowest compilation units

| Duration | Unit | Kind | |---------:|------|------| | 87.7s | aws-lc-sys | build-script | | 57.7s | terraphim_orchestrator | codegen | | 52.5s | libgit2-sys | build-script | | 50.0s | terraphim_tinyclaw | codegen | | 41.3s | terraphim_tinyclaw | codegen | | 38.3s | terraphim_server | codegen | | 37.5s | image | codegen | | 37.5s | terraphim_agent | codegen | | 33.8s | terraphim_mcp_server | codegen | | 33.6s | terraphim_server | codegen | | 31.2s | terraphim_orchestrator | codegen | | 29.9s | terraphim_agent_evolution | codegen | | 29.6s | libsqlite3-sys | build-script | | 29.2s | zstd-sys | build-script | | 27.0s | fff-search | codegen |

Observations for the split

Native build-scripts dominate cold cost (aws-lc-sys, libgit2-sys, libsqlite3-sys, zstd-sys ~= 200s combined). Per-repo builds that do not pull these (e.g. terraphim-core) should be markedly faster -- a key expected win from the split, and the reason the D7 cold-build gate is the tightest.
The heaviest first-party units (terraphim_orchestrator, terraphim_tinyclaw, terraphim_server, terraphim_agent, terraphim_mcp_server) sit in the app/adapter and agent layers -- consistent with the extraction order placing terraphim-core first (cheap, foundational) and the composition roots last.