Improve import handling — convert imports to session history

Imports now create session files with original dates instead of just
reading once and extracting to profile. This provides natural relevance
decay as new sessions accumulate. Also adds post-setup import command.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -147,7 +147,7 @@ Ask these conversationally, one at a time.
 
 > Do you have existing therapy notes to import? (ChatGPT exports, markdown, PDF, text files)
 
-If yes, ask for file paths. Create `{storage_path}/imported/` and process files there.
+If yes, ask for file paths. Store paths for processing during first session.
 
 ---
 
@@ -162,7 +162,6 @@ After gathering all answers, create the therapy environment.
 ├── CLAUDE.md
 ├── profile.md
 ├── sessions/
-├── imported/           (if importing)
 └── .therapy/
     ├── version.json
     ├── safety-protocol.md