Unify all LLM backends to OpenRouter, fix cost tier pricing, and bug fixes

Fix README: correct CLI flags, update tier system, expand CLI reference

MSc_Prod: major update — iteration engine, counsel v2, tree search improvements, CLI overhaul

Improve install instructions: clarify Python 3.10+ requirement with alternatives

Relax dependency pins for public PyPI compatibility

Fix README setup instructions: correct repo URL, output dir, and remove nonexistent commands

PoggioAI/MSc CLI: rebrand and package as installable `msc` command

Update README to match actual codebase: pipeline diagram, agents, CLI flags

Comprehensive audit fixes: build, self-containment, and documentation

Fix Nodes 26-30 round 3: sentinel on None path, duality context injection, Callable import

Fix Nodes 26-30 round 2: wrapper nesting, selective gate clearing, resource_prep tools

Fix Nodes 26-30 audit: authorized_imports, formalized_results state, LaTeX tools, proofreading entry

Fix Nodes 23-25 audit: duality check path, gate safety, PDF key, reasoning_effort

Fix Nodes 21-22 audit: milestone reports, validation gates, state reducers

Address review feedback: report write-path protocol, fix_type docs, conditional retry increment