raggity v0.7.1

Whole-package review hardening. Security: per-identity session isolation (no cross-tenant conversation read/continue/delete), identity-scoped DELETE /session, bounded+closed per-user Raggity cache, SSE errors no longer leak internals, new POST /ingest/content so tenants ingest their own docs. Correctness: embed-cache now keyed by model+dim (no stale-vector corruption on model switch), answer-cache concurrency lock + system-prompt keying + size bound, parent-document retrieval preserves lost-in-the-middle ordering, RRF ordering fixed for hybrid+rerank-off, query transforms resilient to a single LLM failure, loop-safe sync wrappers. Providers: OpenAI/Ollama client closed, empty-choices guard, OpenAI requires a key, subscription mode strips OAuth token too. Storage/connectors: Qdrant local payload indexes, LanceDB version guards, bounded fallbacks, posix/raw-bytes-hash consistency, GitHub SHA refs, web crawl max_pages cap, 16-char citation tags. Tooling: serve --open race fixed, eval input validation, clearer registry errors, resilient watch, pip install -e .[dev] runs the suite, Python 3.13 in CI. 308 tests, 0 warnings. No change to the default single-user/local/Claude path.