/insights report: nav anchors broken and AI analysis sections empty ("No insights generated")

Bug Description

Running /insights generates a report with two distinct problems:

1. Navigation links are broken — the top nav TOC links point to #section-work, #section-usage, #section-wins, #section-friction, #section-features, #section-patterns, #section-horizon, #section-feedback, but none of those id attributes exist anywhere in the rendered HTML. Clicking them does nothing.

1. AI analysis sections are empty — the insights generation phase returns {} (empty JSON), causing all AI-powered sections to render as "No data" or to be completely omitted. The CLI output also shows:

``
_No insights generated_
``

Affected Sections

All of these sections are empty / show "No data":

• What You Work On
• Session Types (chart)
• What You Wanted (chart)
• What Helped Most
• Outcomes
• Primary Friction Types
• Inferred Satisfaction
• Impressive Things
• Where Things Go Wrong
• Features to Try
• New Usage Patterns
• On the Horizon
• Team Feedback

What Does Work

The sections that don't require AI analysis render correctly:

• Summary stats (messages, files, lines, days)
• Top Tools Used (bar chart)
• Languages (bar chart)
• User Response Time Distribution
• Multi-Clauding / Parallel Sessions
• User Messages by Time of Day (with timezone selector)
• Tool Errors Encountered

Steps to Reproduce

1. Run /insights in Claude Code
2. Open the generated report.html file
3. Click any nav link in the TOC → no scrolling occurs
4. Observe that all AI-generated sections show "No data" or are absent

Environment

• Session metadata files present and parseable (valid JSON, standard format)
• Sessions span multiple weeks with hundreds of messages
• The facets/ directory was not created (only session-meta/ exists in the usage-data folder)

Expected Behavior

• Nav links should scroll to the corresponding sections
• AI analysis should produce insights (suggestions, wins, friction patterns, recommended features, etc.) when sufficient session data exists

Actual Behavior

• Nav links are dead (target IDs missing from DOM)
• AI analysis returns {}, leaving the majority of the report blank