/insights command generates empty report despite 98 analyzed sessions

Description

Running /insights produces a report that is far too short to be useful and doesn't surface any actual patterns from usage.

Steps to reproduce

1. Run /insights in a session with substantial history (98 sessions analyzed, 862 messages, ~803h logged, spanning 2026-06-16 to 2026-07-27)
2. Report is generated at ~/.claude/usage-data/report-<timestamp>.html

Expected

A report that surfaces meaningful patterns: most-used skills/projects, time distribution, common workflows, friction points, etc., proportional to the amount of session history available.

Actual

The report's insights payload came back essentially empty:

{}

At-a-glance summary rendered:

109 sessions total · 98 analyzed · 862 messages · 803h · 1 commits
2026-06-16 to 2026-07-27
_No insights generated_

No facets directory was created (~/.claude/usage-data/facets does not exist) despite the command message referencing one.

Environment

• Multiple sessions across several projects (claude, design-system-ai-utils), heavy skill usage (daily-dashboard, week-review, context-update, pay-triage, etc.)
• Re-running the command produced the same empty result on a second attempt (report-2026-07-27-105704.html and report-2026-07-27-112248.html are near-identical in size, both effectively empty of generated insights)

Impact

/insights is unusable for actually understanding usage patterns — it just returns the raw session-count summary line with no analysis body.