docs: align README and strengthen Silver evidence

[JacobOptimiza]

README parity

• Single Why DevNav / Por qué DevNav section in each README (duplicate five-bullet section removed).
• EN sections rewritten to match the ES structure: first-run with the scripts/agents alternative, global favorites (full steps), shortcuts grouped as Navigation and selection / Agents / Organization, search and actions / Custom commands / Language.
• English FAQ added (9 questions mirroring the Spanish FAQ) linking to TROUBLESHOOTING.md anchors.
• ## Desarrollo renamed to ## Compilar desde fuente with the clone/-BuildFromSource block, matching ## Build from source.

Current development gates

Both READMEs now list the versioned coverage gates from #43 (cargo-llvm-cov + rust-production-coverage.py, analyzer unit tests, invoke-pester-coverage.ps1, invoke-npm-coverage.ps1) instead of the bare Invoke-Pester call.

Security expectations

SECURITY.md gains a Security expectations section (local config, SHA-256 integrity vs signatures, not-a-sandbox scope, v0.13.0 not signed, CodeQL Rust extraction residual) without changing the reporting policy. Both READMEs link SECURITY/ARCHITECTURE/ASSURANCE/CONTRIBUTING/troubleshooting; EN adds the Dependabot bullet (ES already had it).

12-month roadmap horizon

ROADMAP.md gains a Planning horizon section: keeps Windows x64/ARM64, native Rust+PowerShell, GitHub Release/npm/Scoop paths, WinGet pursuit; explicitly excludes Linux/macOS claims and JS-runtime core.

Validation

Local paths/anchors verified (9/9 EN FAQ anchors exist in TROUBLESHOOTING.md); documented commands map to real files; H2/H3 parity EN/ES (12 H2, 25 H3 each); WinGet still pending; no versions/releases touched. No functional changes.