feat(stack): drop qdrant and embedding-server, use OmniRoute's built-in memory

OmniRoute's memory feature is self-contained: its bundled sqlite-vec
vector store plus a local ONNX embedding model (Transformers.js,
~400MB, fetched into the omniroute-data volume on first use) replace
the external qdrant + bge-small-en-v1.5 embedding-server pair, which
was never wired up in the dashboard. Two fewer containers, no
second GGUF download, no EMBEDDING_MODEL_FILE var. Memory stays
opt-in via the dashboard (Settings -> Memory, transformers source);
nothing here changes the gateway's static config.

README.md

@@ -37,4 +37,4 @@ The gateway also fronts SearXNG-backed web search — see `docs/research/litellm
 ## What's not here
 
 - **Open WebUI** — this stack has no chat UI; every client is a coding CLI. Removed rather than kept idle.
-- **Gateway-level knowledgebase/memory** (`litellm-pgvector`, `pgvector-db`, a dedicated embedding model) — removed as unwanted, unrelated to OmniRoute's own lack of parity with it (see issue #31's #34). Superseded by OmniRoute's own memory feature, backed by `qdrant` and `embedding-server` (bge-small-en-v1.5, CPU-only) — both bare services, wired up as a memory provider by hand in the dashboard, no static routing config here.
+- **Gateway-level knowledgebase/memory** (`litellm-pgvector`, `pgvector-db`, a dedicated embedding model) — removed as unwanted, unrelated to OmniRoute's own lack of parity with it (see issue #31's #34). Superseded by OmniRoute's own built-in memory feature (opt-in via the dashboard, Settings → Memory): vector store is its bundled `sqlite-vec`, embeddings are a local ONNX model (Transformers.js, ~400MB, downloaded into the `omniroute-data` volume on first use) — no external services, no static config here.