feat(validator): add bare FastAgent + Pallas validator for Mnemosyne MCP

A self-contained sub-project under validator/ that wraps Mnemosyne's MCP
server in a single FastAgent. Use it to confirm — outside of Daedalus —
that Mnemosyne's MCP transport works, every tool registers, args/responses
round-trip, and an LLM can actually drive the tools.

The validator is its own Pallas-consuming project with its own pyproject
(pallas-mcp + fast-agent-mcp), agents.yaml, and fastagent.config.yaml —
matching the pattern used by Iolaus and other Pallas consumers. It does
not import Mnemosyne Python code; it only speaks MCP over HTTP.

The agent never sets workspace_id, so all calls run against the global
scope (libraries with workspace_id IS NULL). Workspace-scoped validation
will come once Daedalus's chat path is wired (Daedalus injects
workspace_id server-side, force-overwriting whatever the LLM produces).

Default model is openai.Qwen3.5-35B-A3B-UD-Q4_K_XL.gguf served by
llama.cpp at nyx.helu.ca:22079/v1. Token provisioning via
`python manage.py create_mcp_token --user <u> --name validator`.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

validator/agents.yaml

@@ -0,0 +1,17 @@
+# Mnemosyne Validator — Pallas deployment topology
+#
+# A single-agent Pallas project whose only purpose is to validate the
+# Mnemosyne MCP server end-to-end. Not a production deployment.
+
+name: mnemosyne-validator
+version: "0.1.0"
+host: localhost
+namespace: ca.helu.mnemosyne-validator
+registry_port: 24300
+
+agents:
+  mnemosyne_validator:
+    module: agents.mnemosyne_validator
+    port: 24301
+    title: Mnemosyne Validator
+    description: "Exercises Mnemosyne's MCP tools: search, get_chunk, list_*, get_health"