docs(readme,security,contributing): meet the repo standard — 0 ERROR

The per-repo gate flagged four ERRORs and two WARNs. Fixed, in the order the
work actually gets done in:

MISSING
- `## Honest limitations` -> `## Known limitations`, `## Out-of-scope
  (documented boundary)` -> `## Non-goals`. Both sections existed under names
  no reader or agent scans for; the contract wants predictable top-level
  headings. Pointers followed: the in-README anchor, SECURITY.md's out-of-scope
  preamble, CONTRIBUTING.md's scope section, and the consumer-facing
  docs/ADOPTION-BRIEF.md. Historical records (CHANGELOG, docs/PLAN.md,
  docs/OKF-INGESTION-BRIEF.md) keep the name they were written with.

WEAKENING
- README now opens with one line identical to the forge description, above the
  badges. That is the only place a machine can check description == README.
- Forge description shortened 207 -> 178 codepoints (bound 180), and the same
  string written to pyproject's `description` so the fourth copy cannot drift.

The tests badge is dropped, not updated. `tests-699_passing` as a static image
is a claim dressed as evidence: there is no CI runner on this forge, so nothing
verifies it. Replaced with the honest substitute in Install — the single command
that runs the suite from a clean clone, stated together with the fact that
nothing runs it automatically.

Two WARNs deliberately left standing:
- H1 `# llm-ingestion-guard` != repo name. The register itself records
  llm-ingestion-guard as "a package, not a repo"; the H1 names what you pip
  install. Renaming the repo is the operator's call, not this commit's.
- The `Status` badge trips the same claim-badge regex, but `alpha` asserts
  maturity, not a run — the same reason version/license/platform are exempt.
  Measured false positive in the gate's classifier, reported upstream.

pyproject.toml

@@ -5,7 +5,7 @@ build-backend = "hatchling.build"
 [project]
 name = "llm-ingestion-guard"
 version = "0.3.4"
-description = "A minimal, dependency-light defensive layer for LLM ingestion pipelines — the write-time siblings of query-time chatbot guardrails."
+description = "Write-time defensive layer for Python pipelines that persist LLM output: sanitize, fence, tool-less quarantined transform, capability isolation, scan before persist, fail-secure."
 readme = "README.md"
 requires-python = ">=3.10"
 license = { file = "LICENSE" }