[dovvnloading]

Changes

• Build each AI request from the selected node's ancestry; stop relying on a global mutable conversation history. Regeneration uses the same branch-specific context.
• Capture full scene snapshots (nodes, edges, frames, charts, notes, pins, view state), detect unsaved edits before new/load/close, and preserve notes-only canvases.
• Save chats plus their notes and navigation pins in one SQLite transaction, avoiding partial commits.
• Correct modular app dependencies (PySide6 and API providers), create separate requirements for the archived PyQt5 file, fix the README launch command and model-pull instructions, and warn when Ollama task models are missing.
• Add regression tests and a GitHub Actions workflow.

Test plan

• python -m compileall -q graphite_app/graphite_app
• QT_QPA_PLATFORM=offscreen python -m unittest discover -s tests -v
• Manual Qt smoke test: create two independent branches, save notes-only canvas, edit notes then load/new/close with Save/Discard/Cancel, restart Graphite, verify default model warnings.

These fixes target the modular graphite_app/graphite_app/ implementation named by the README as the active source. The archived top-level Graphite.py remains a separate historical implementation.