docs: design brief for reusable LLM ingestion-pipeline security library

Brief-stage repo. docs/BRIEF.md defines a minimal, framework-agnostic
library that packages the write-time ingestion contract (sanitize ->
fence -> tool-less quarantined transform -> per-stage capability
isolation -> scan output before persist -> fail-secure) as reusable
code. Positioned honestly against query-time guardrails (LLM Guard,
NeMo, Rebuff, Vigil) with a prior-art verification log. Reference
implementation: claude-code-llm-wiki Stage B.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HPAmFyEVWbwvmSNVdXTu4d

CLAUDE.md

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+# llm-ingestion-pipeline-security
+
+## Kontekst
+
+Gjenbrukbar, minimal defensiv layer for LLM **ingestion**-pipelines (write-time),
+til forskjell fra query-time chatbot-guardrails. Pakker det arkitektoniske
+kontraktet — sanitize → fence → tool-less karantenert transform → per-stadium
+capability-isolasjon → scan output før commit → fail-secure — som komponerbar,
+framework-agnostisk kode.
+
+Referanse-implementasjon: `claude-code-llm-wiki` Stage B (`tools/wiki_ingest/`).
+Lexikon-seed: `injection-patterns.mjs` fra `llm-security`-pluginen.
+
+Repoet er på **brief-stadiet**. Start med `docs/BRIEF.md`.
+
+## Konvensjoner
+
+- Norsk for dialog og planer, engelsk for kode og innhold (repoet er ment publisert).
+- Ingen GitHub — kun Forgejo (`git.fromaitochitta.com`) hvis/når publisert.
+- Ingen remote satt ennå; ingen push før operatøren bestemmer publisering.
+- Minimal-dependency: stdlib-first kjerne; ML/judge-detektorer bak extras.