Track PiComms replacement with thin Pinet nvim adapter

[gugu91]

Context\n\nMaintainer clarified in Slack thread 1777814752.955529 that PiComms appears to be the original idea for Pinet and should be rethought: remove/replace PiComms with Pinet, with a thin Neovim adapter. This is lower priority than immediate stabilization.\n\n## Immediate follow-up\n\nA separate maintenance change should disable PiComms in the current nvim environment now, without landing the full adapter rewrite.\n\n## Tracking scope\n\n- Design a thin Neovim adapter over Pinet rather than maintaining a second persistent comment system.\n- Decide the adapter command shape (for example :PinetAsk, :PinetRead, or direct send/delegation helpers).\n- Remove or migrate any remaining PiComms-specific docs, skills, tools, slash commands, panel UI, and local storage once the replacement path is agreed.\n- Keep the useful nvim bridge primitives: editor context sync and open_in_editor.\n- Preserve Pinet progressive-discovery/token-footprint constraints; do not add large hot-path schemas.\n\n## Prior exploration\n\nPR #713 explored a full replacement but was closed before merge because the maintainer asked to keep the immediate action smaller: disable now, track the fuller rethink here.\n