fix: keep lcm_describe details middleware-safe

[jalehman]

What

Keeps lcm_describe's structured details payload compact while preserving the full human-readable description in the text content.

Why

After #633 fixed runtime name lookup, lcm_describe could execute but OpenClaw's tool-result middleware rejected the result as invalid and replaced it with:

Tool output unavailable due to post-processing error.

The likely cause is that lcm_describe duplicated the full summary content and entire subtree in details, which can exceed OpenClaw's middleware details shape/size bounds. The text output already contains the useful content, so details should stay metadata-sized.

Changes

• Strip large summary.content and raw summary.subtree from details
• Strip file explorationSummary/storageUri from file details and replace with hasExplorationSummary
• Keep the existing manifest budget annotations in details.manifest
• Add regression coverage that summary content/subtree are not duplicated into details

Testing

• npm test -- test/lcm-tools.test.ts
• npm test -- test/lcm-tools.test.ts test/manifest.test.ts
• npm test
• npm run build
• git diff --check

Note: npx tsc --noEmit --pretty false still reports the existing repo-wide type debt seen before this change; no new lcm_describe-specific issue was observed.