Add option to loads `percent.json` from locally

Before per-filter downloaded `stats.json` files read from disk, stats.json files are indexing for reading targets by remotely fetches `percent.json`.

On a machine without network access, yarn `build:local` fails at the `percent.json` fetch — the advertised offline workflow does not work. Also, because `percent.json` changes remotely.

Each builds of the same pinned stats snapshot can differ. The set of optimizable filters is not pinned.

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**Goal:** Support a dependency injection option to load `percent.json` locally. For example, directly using it from `./optimization_config.json` in the FiltersRegistry project.