Meta-hardening: docs + tests only (zero runtime change)

Scope

Meta-hardening pass: legibility, security policy, and invariant test coverage.

Constraint: ZERO runtime semantic change.

Added

• SECURITY.md — security disclosure policy
• docs/runtime-trace.md — runtime trace walkthrough
• docs/architecture-diagram.md — ASCII architecture diagram
• tests/__init__.py + tests/test_invariant_enforcement.py — 16 structural invariant tests
• CI step: Run invariant tests (python -m pytest tests/ -v)
• CHANGELOG.md meta-hardening entry

Invariants enforced

• EXIT_ENUM: exactly {ALLOW, HOLD, DENY, SILENCE}
• StopMachine: RED is terminal, no escape
• Gate boundary: valid envelope != DENY, invalid envelope == DENY
• No runtime imports from docs/analysis/artifacts/examples
• Primitive folders exist and are non-empty
• LICENSE and README.md present

Runtime files unchanged

• stop_machine.py — untouched
• gate.py — untouched
• rules.py — untouched
• envelope_parser.py — untouched
• primitives/* — untouched

PR #7 | Squash-merged | All CI green

Geometry Layer v0 — Log-only instrumentation (spec FROZEN)

What's Changed

• v0.4: Fix collision + ensure root tests run in CI by @LalaSkye in #1
• v0.5: Legibility pack – stub v0 folders, add drift alarms, remove v0 demos by @LalaSkye in #2
• PR#1: Geometry Layer v0 — Docs only (no code changes) by @LalaSkye in #3
• PR#2: Geometry Layer v0 — Instrumentation (gate.py emission hook) by @LalaSkye in #4
• Geometry Layer v0: CI non-gating analysis job + artefact upload + drift alarm by @LalaSkye in #5
• PR#4: Geometry Layer v0 — Freeze spec + README badge by @LalaSkye in #6

New Contributors

• @LalaSkye made their first contribution in #1

Full Changelog: v0.1.0...geometry-layer-v0

v0.1.0 — Initial release

Changelog

Added

• State enum (GREEN, AMBER, RED) with @unique constraint
• StopMachine class with deterministic three-state lifecycle
• advance() — move to next state in sequence
• transition_to(target) — explicit validated transition
• reset() — return to GREEN from any state
• is_terminal property — True when RED
• TerminalStateError — raised on transition from RED
• InvalidTransitionError — raised on illegal transition target
• Comprehensive test suite (187 lines, covers every transition and failure mode)
• Operational README with quickstart, constraints, and test instructions
• MIT license

Constraints enforced

• Deterministic behaviour only
• No global state
• <200 LOC implementation (98 lines)
• All transitions explicit via lookup table
• RED is terminal — no implicit transitions