feat(ai): BYOK per-request key/baseURL resolution seam

[rickylabs]

Part of #238

Handle: FAI-11 · Milestone: 0.0.1-beta.7 · Lane: WSL Codex. Dep: FAI-10.

Scope — BYOK per-request key/baseURL resolution seam (gap 4, previously un-issued)

Provider factories take static apiKey/baseURL at construction (verified §12); multi-tenant/user-supplied keys need a per-request override the current config cannot express (analysis/F-ai/02 §4).

Acceptance

• A per-request key/baseURL override seam (incl. Ollama host) that adapters resolve without an app hand-rolling an override layer.
• gate:jsr on the changed @netscript/ai surface (deno doc --lint clean, deno publish --dry-run green).

Design source: design/F-ai/epic-and-issues.md (FAI-11).

[rickylabs]

Dependency edge (DAG second pass): Depends on #460 (FAI-10).