docs: refresh public project guidance

[ferueda]

Summary

• reduce the root README to the install, permission, first-use, evidence, and local-data paths
• replace the completed 1,685-line implementation history with a concise current roadmap focused on M13
• rewrite release guidance around the routine Release Please and trusted-publishing flow
• remove stale pre-alpha, pending-release, and future-Cursor wording from current contracts and contributor docs

Why

The public entry point repeated detailed CLI, storage, indexing, and performance contracts that already have focused owners. The roadmap also still said M12 rollout was pending after 0.1.0 and 0.1.1 were published and verified. This made the repository harder for humans and agents to install, understand, and maintain.

Impact

No runtime behavior, CLI schema, storage contract, or privacy boundary changes. README drops from 255 to 133 lines and the roadmap from 1,685 to 142 lines. Exact behavior remains in the CLI, structured-output, privacy, architecture, and provider references.

Verification

• pnpm check:docs
• pnpm check — 107 test files / 1,107 tests, build, dist smoke, and package smoke
• independent docs-drift-review — one stale architecture wording issue found and fixed; no advisory bloat findings