feat: add provider-neutral LLM layer with secrets, budgets, recording and prompts

Phase 7 (ADR-0004). Cognitive code asks the router for a role; the
router maps roles to configured models with ordered fallbacks, applies
global and per-mind daily token budgets and a concurrency limit, records
every call (request, response, usage, latency, cost, seed, request hash)
and can serve recordings back for exact replay. Providers are raw HTTP
clients for OpenAI-compatible, Anthropic and Ollama endpoints, with
embedding support for the embed role wired into memory retrieval.

Secrets are references only: env:, file:, or enc: values encrypted with
AES-256-GCM under NOEMA_MASTER_KEY; keys are resolved at call time and
never rendered, logged or exported. Outbound HTTP refuses private and
loopback addresses at dial time unless a provider explicitly allows it,
bounds redirects and caps bodies. Provider errors are scrubbed.

Prompts are named, versioned rows with system and user templates and an
optional JSON schema; untrusted text enters only through delimited data
blocks. Six defaults are seeded and never overwritten. The UI adds the
LLM page (providers, models, role matrix, usage, errors, budgets), a
provider page with connectivity test, and a prompt manager with editor,
test runner, history, restore, clone and diff. CLI: provider, prompt.

CHANGELOG.md

@@ -5,6 +5,7 @@ All notable changes to Noema are recorded here. Format follows Keep a Changelog;
 ## [Unreleased]
 
 ### Added
+- Phase 7 LLM layer: provider-neutral router with roles and fallbacks, OpenAI-compatible/Anthropic/Ollama providers, encrypted secret references, SSRF-safe HTTP client, budgets, full call recording with replay, versioned prompts with untrusted data blocks, configuration and prompt manager UI, CLI.
 - Phase 6 beliefs: evidence-derived confidence with inspectable arithmetic, statuses, alternatives, append-only history, deterministic contradiction detection, temporal-association hypotheses, operator corrections (wrong, do-not-infer, inaccurate memory), belief explorer and CLI.
 - Phase 5 memory: episodic/semantic/procedural/autobiographical memory with epistemic status, fused retrieval with inspectable component scores, optional pgvector embeddings, decay without deletion, attention-gated encoding, retrieval process, memory explorer and CLI.
 - Phase 4 cognition core: deterministic attention scoring with inspectable breakdowns, global workspace and working memory with decay, per-mind cognitive runtime with bounded concurrent processes, loop detection, operator controls, live workspace page and CLI.