feat: initial commit — repo scaffold and v1 scope

Scope settled 2026-07-16: implements portfolio-optimiser-commons
ingest-spec (commons keeps spec authorship), Python 3.10+ stdlib-only
core, security delegated to llm-ingestion-guard at persist gates.
Doors: spec-based ingestion, bundle inbox (md/txt/csv/json/html core,
binary formats behind [extract]), external bundle import.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QeqhJpYQyghASjiJo5EhGg

.gitignore

@@ -0,0 +1,21 @@
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+dist/
+build/
+*.egg-info/
+.pytest_cache/
+.mypy_cache/
+.ruff_cache/
+.coverage
+
+# Environment / local
+.env
+.env.*
+*.local.md
+.DS_Store
+
+# Local-only: public remote — never publish session state or internal briefs
+/STATE.md
+/docs/oppstartsprompt.md