feat(memory): restore lost subsystems + modernize templates module (#55)
Port missing subsystems from old memory bank:
- symbolic module + 7 handlers (fragmented memory extraction, AUDN dedup)
- templates module + 3 handlers (pusher, differ, spawn_pusher)
- pool_processor intake handler
Modernize templates system (FPLAN-0052):
- Fix all imports (MEMORY_BANK → aipass.memory, cli → aipass.cli)
- Remove hardcoded paths, use Path(__file__) traversal
- Add seedgo-compliant introspection gate to templates.py
- Update canonical templates to v2 schema (entry-count limits)
- Create spawn_pusher.py handler for auto-discovering spawn template sets
- Wire spawn_pusher into push-templates command
Co-authored-by: @memory <memory@aipass>
