feat: AI Copilot Terminal User Interface (TUI) Implementation

[Makeepan-dev]

Description

Following the feedback in #1318 regarding the WebUI scope, I have pivoted the AI copilot implementation to a native Terminal User Interface (TUI). This allows for a powerful, interactive assistant that functions within CLI-driven environments, keeping the WebUI dedicated to administrative tasks.

Fixes

TUI entry point: Created internal/cmd/copilot/main.go using the charmbracelet/bubbletea library.
Architecture: Implemented the Model-View-Update (MVU) pattern for smooth asynchronous terminal interactions.
Sidecar Backend: Integrated Python gPRC logic within internal/cmd/copilot/python/ to handle AI analysis logic separately from the Go collector.
Standards Compliance: Adhered to the internal/cmd project structure for standalone utilities.

Motivation:
To provide a lightweight, high performance assistant for database metrics analysis that aligns with the maintainers' vision for the pgwatch ecosystem.

AI & Automation Policy

• I am the human author and take full personal responsibility for every change in this PR.
• No AI or automated generative tool was used in any part of this PR OR I have disclosed all tool(s) below.

AI/automation tools used (leave blank if none):
Gemini: Used to draft the initial TUI structural template and ensure the Go gRPC client boilerplate follows patterns.
All logic, state management and file pathing have been manually reviewed, refined and tested on my local environment (Windows/Linux)
internal/cmd/copilot

Checklist

• Code compiles and existing tests pass locally.
• New or updated tests are included where applicable.
• Documentation is updated where applicable.

[Makeepan-dev]

Hi @pashagolub (Pavlo),
Following our recent discussion regarding the architectural direction for the AI Copilot, I have officially submitted my GSoC 2026 proposal for this project.As discussed, I have fully pivoted this PR from the initial WebUI implementation to a native Terminal User Interface (TUI) architecture. The current state of this PR reflects the 'Phase 1' milestones outlined in my proposal, including:

• TUI Foundation: Implementation of the Bubble Tea MVU architecture in internal/cmd/copilot/.
• Backend Sidecar: A gRPC-based Python logic handler to ensure the main Go collector remains lightweight.
• AI Policy Compliance: Full disclosure and manual review of all boilerplate in accordance with the project's requirements.I am committed to a 30+ hours per week schedule to see this 350-hour project through to completion. I look forward to your feedback on the TUI structure!Best
• regards,
• Mageepan (Makeepan-dev)

[pgulb]

@Makeepan-dev I think you mistyped someone's else username

[Makeepan-dev]

@Makeepan-dev I think you mistyped someone's else username

Sorry