feat(cps): scan @imported files for volatile cached-prefix content (v5.10 B6) [skip-docs]

CPS originally inspected only files discovery classifies as claude-md, but a
CLAUDE.md can pull arbitrary files into the cached prefix via @import — and
those targets (e.g. @shared/conventions.md) are usually not claude-md in
discovery, so their inlined content was never scanned. Neither TOK Pattern A
(top-30 of cascade files) nor the in-file CPS scan reaches past the importing
file, so volatility inside an imported file was invisible.

B6 closes the gap: for each @import whose import site sits within the
cached-prefix window (imp.line <= CACHED_PREFIX_LINES), CPS resolves the path
(resolveImportPath, mirroring import-resolver/token-hotspots semantics), reads
the target, and runs findVolatileLines over its first 150 lines. A hit emits a
distinct medium finding — "Volatile content in @imported file breaks cached
prefix" — keyed on the resolved file, evidence naming the importer.

Scope boundaries (deliberate):
- One hop only; imports-of-imports stay with IMP (deep-chain owner).
- No lines-1-30 skip for imported content — that exclusion is root-file-specific
  to avoid Pattern A overlap, which never reaches imported files.
- No double-reporting: an import resolving to a discovered claude-md is skipped
  (own iteration); a reportedImports set dedupes a target imported by several
  CLAUDE.md files.

Dropped from B6 (per plan verdict): confident behavioral cache-buster detection
(opusplan/model-switch is runtime, not static config) and jq-transcript
automation. "No overstated behavioral finding ships" — even the permitted
opusplan info-advisory was left out; the @import extension is the whole of B6.

Byte-stability: the in-file finding keeps the same condition + byte-identical
evidence/description (continue-skip refactored to if-emit, behaviour-preserving);
new findings fire only on a volatile import, which no frozen v5.0.0 fixture has.
docs: README + scanner-internals CPS rows + full B6 note; CLAUDE.md kept lean
([skip-docs]). Suite 1254 -> 1257 green; snapshots + SC-5 untouched.
Version/badges/CHANGELOG wait for the v5.10 release cut.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -323,7 +323,7 @@ By default, `/config-audit` auto-detects scope from your git context. Override w
 | `conflict-detector.mjs` | CNF | Settings contradictions across scopes, permission conflicts, hook duplicates |
 | `feature-gap-scanner.mjs` | GAP | 25 feature checks shown as opportunities, not grades — plus a conditional `disableBundledSkills` recommendation when the active skill listing is over budget, and a conditional **filter-before-Claude-reads** lever when a hook injects unfiltered output into `additionalContext` (companion to the HKV advisory; cites the documented `filter-test-output.sh` pattern) |
 | `token-hotspots.mjs` | TOK | Cache-breaking volatile content, redundant tool permissions, deep import chains, oversized cascades, bloated skill descriptions, MCP tool-schema budget, and stale `~/.claude/plugins/cache` versions (disk-cleanup, zero live-context impact) — cache-aware ranking excludes superseded plugin versions by default (`--no-exclude-cache` to include) |
-| `cache-prefix-scanner.mjs` | CPS | Volatile content in lines 31–150 of the CLAUDE.md cascade — beyond the cache-prefix window but still re-loaded every turn |
+| `cache-prefix-scanner.mjs` | CPS | Volatile content in lines 31–150 of the CLAUDE.md cascade — beyond Pattern A's top-30 window but still re-loaded every turn — **plus** volatile content inside `@import`-ed files (inlined into the cached prefix, one hop, otherwise invisible to per-file scans) |
 | `disabled-in-schema-scanner.mjs` | DIS | Dead/ineffective permission entries: (1) tools in BOTH `permissions.deny` and `permissions.allow` — deny wins (incl. the `Tool(*)` deny-all glob, equivalent to a bare deny); (2) unanchored allow wildcards (`*`, `B*`, `mcp__*`) that Claude Code silently skips — valid only as `mcp__<server>__*`; (3) `Tool(param:value)` rules whose key is the tool's own canonicalizing field (`command`/`file_path`/`path`/`notebook_path`/`url`) — CC ignores these and emits a startup warning |
 | `collision-scanner.mjs` | COL | Cross-plugin skill name collisions; user-vs-plugin overlaps |
 | `skill-listing-scanner.mjs` | SKL | Skill-listing token budget: a single skill description over the ~1,536-char listing cap Claude Code truncates (`CA-SKL-001`), and the summed active-skill descriptions exceeding the ~2%-of-context listing budget (`CA-SKL-002`) |