fix(benchmarks): rebuild every branch-versioned module before an A/B run

[DemchaAV]

Why

The A/B scripts installed only the engine module, but benchmarks/pom.xml resolves graph-compose-render-pdf and graph-compose-templates — plus the templates tests-classifier jar, which is deliberately never published — at ${graphcompose.version}, i.e. the branch's own version.

So both sides of an A/B took those two jars from ~/.m2. When the compared branches share a version, which is the normal case for two branches cut from develop, they took the same ones: any change in the PDF backend or the templates module measured a delta of exactly zero. A stale backend jar built against the other branch's core could also throw NoSuchMethodError mid-run instead of reporting a number.

What

scripts/ab-bench.sh and scripts/run-benchmarks.ps1 now install render-pdf and templates per branch alongside the engine, each guarded by the presence of its pom so a pre-split layout — where the root build produces them — still works. This mirrors the install sequence the CI performance job already uses (.github/workflows/ci.yml:346-361).

graph-compose-fonts is left alone deliberately: it tracks an independent version line, so it does not change with the branch under test.

Tests

Both scripts parse clean (bash -n, PowerShell AST parser).

The install logic itself was exercised end to end across the layout boundary while investigating engine performance: 8 build-and-measure cycles over v1.8.0, v1.9.1, v2.0.0, v2.1.0 and develop, in a detached worktree. v1.8.0 predates the module split and has no render-pdf/ or templates/ directory, so it takes the guarded-skip path; the 2.x refs take the install path. All eight produced benchmark output.

scripts/ab-bench.sh itself was not run end to end here — its own CI smoke (ab-bench-smoke.yml) covers that and fires on changes to the script.

[DemchaAV]

The ab-bench.sh smoke (main vs develop) check fired on this change and passed, so the script now runs end to end with the added per-branch installs — the verification the description deferred to CI.