v4.0.0 — complete the computational-neuroscience memory model

• Merge pull request #76 from cdeust/wip/da-active-forgetting
• test: update tool-count + heat-writer invariants for v4.0
• style: ruff format + lint fixes across the v4.0 modules
• Merge origin/main (v3.25.0) into wip/da-active-forgetting (v4.0.0)
• fix(tests): replace insecure tempfile.mktemp with mkstemp (CodeQL CWE-377)
• release: v4.0.0 — complete the computational-neuroscience memory model
• ci: make HF model pre-download resilient and pin tests offline (#75)
• docs(readme): global review — v3.25.0 refresh (#74)
• wip(forgetting): A2 DA active-forgetting handler + wiring + handoff bundle

What's Changed

• docs(readme): global review — v3.25.0 refresh by @cdeust in #74
• ci: resilient HF pre-download + offline tests (fix main CI flake) by @cdeust in #75
• release: v4.0.0 — complete the computational-neuroscience memory model by @cdeust in #76

Full Changelog: v3.25.0...v4.0.0