Gemini / Perplexity / Character.ai import support in legacy_importer.py

[ajsupplycollc]

What

Extend tools/legacy_importer.py to support importing conversation history from:

• Google Gemini (via Google Takeout)
• Perplexity AI
• Character.ai

Currently supports Claude and ChatGPT exports.

Why

The "Session 000" seeding story is one of Adam's strongest pitches — import your old conversations and your AI starts with real history instead of blank. More import formats = more people who can start with a populated Vault on day one.

What exists

tools/legacy_importer.py already handles:

• Claude JSON exports → Vault session format
• ChatGPT JSON exports → Vault session format

The pattern is: parse export → extract sessions → write as Vault-compatible markdown → optionally ingest into neural graph.

What to add

Each new format needs:

1. A parser for that platform's export format
2. Mapping to the Vault session schema (date, turns, topics)
3. Test fixtures with sample export data (synthetic, not real conversations)
4. Documentation in the script's help text

Gemini is highest priority since Google Takeout exports are standardized.