Affected 3.0: universal proof-backed ecosystem coverage

[aspix2k]

Goal

Expand Affected from broad multi-ecosystem support into a proof-backed universal JetBrains workflow: one action, one prepared plan and one Run session per build-system root across every explicitly supported product, language, build system and test runner.

Acceptance criteria

• Maintain one source-of-truth matrix for product × language × build system × test runner × OS × IDE/tool version.
• Every supported cell declares its selection unit: exact test, test file, module/package/project fallback, or unsupported.
• Every support claim maps to public native fixtures and executable regression/conformance gates.
• The same background preparation, atomic revision, busy-state and one-Run invariants apply to every adapter.
• Unknown, incomplete or incompatible metadata remains conservative without splitting a compatible root into multiple Run sessions.
• README and Marketplace text are generated or checked against the proven matrix and remain concise.
• Performance budgets cover startup, edit-to-ready latency, click-to-Run latency, CPU, memory and cache size.
• All child issues in this milestone are complete before 3.0.0.

Owner: @aspix2k / Codex
Priority: high
Dependency: starts after the 2.0.1 affected-run regression fix.