🔧 Internal: Migrated all print() output to structured logging

[ayushh0110]

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What changed

We've migrated all print() calls across 36 source files (~250 calls) to Python's logging module. This is a purely internal change — no features were added or removed, and no APIs changed.

All log output now goes through a centralized screenmind.* logger hierarchy and writes to stderr (never stdout).

Why

1. MCP stability — ScreenMind's MCP server uses stdio transport. Any stray print() to stdout corrupts the protocol and crashes IDE integrations (Cursor, VS Code, etc.). This was the fix(deps): bump pydantic to >=2.11.0 for mcp[cli] compatibility #1 cause of MCP connection drops.

2. Log levels — You can now filter by severity (DEBUG, INFO, WARNING, ERROR) instead of grepping through unstructured output.

3. File logging — You can now write logs to a file for easier debugging and sharing.

New environment variables

Variable	Default	Description
SCREENMIND_LOG_LEVEL	INFO	Set to DEBUG for verbose output, WARNING for quiet
SCREENMIND_LOG_FILE	(none)	Set to a path (e.g. screenmind.log) to enable rotating file logging (10MB × 3 backups)

Example — enable debug logging + file output:

SCREENMIND_LOG_LEVEL=DEBUG SCREENMIND_LOG_FILE=screenmind.log python main.py

If something breaks

This migration touched 36 files. While we've run extensive verification (411 tests passing, structural audits, runtime import checks, MCP stdout contamination tests), if you encounter any issues:

1. App crashes on startup → Set SCREENMIND_LOG_LEVEL=DEBUG and share the output in a bug report
2. MCP connection drops → This should be fixed by this change. If it still happens, open an issue with your MCP client logs
3. Missing output you relied on → Some messages changed from stdout to stderr. If you were piping ScreenMind's output, redirect stderr: python main.py 2>screenmind.log
4. Rollback → If needed, you can revert to the previous version: git checkout 71bbb4c

For contributors

New coding conventions are documented in CONTRIBUTING.md:

• No bare print() — use logger.info() / logger.warning() / logger.error() instead
• No emoji in logger messages — they crash on Windows terminals
• Logger namespace — always logging.getLogger("screenmind.<module.path>")
• CI now enforces these rules via flake8-print and 3 automated convention tests

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Commit: a3e621a — 39 files changed, +608/-346 lines