Add configurable skills and MCP system

[akbad]

Main changes in this PR

• Added first set of Bureau-provided skills (6 editing modes)

  • Included scripting for automatic installation/removal of these skills for all Bureau-supported coding agents

• Added full support for fully & concretely specifying MCPs & skills in YML configs for maximal DRYness and user customizability

  • Implemented and documented full config schema for specifying MCPs' required settings & deps
  • Added scripted automation for setting up config-specified MCPs for all Bureau-configured coding agents
  • Removed hard-coded MCP choices and functionality idiosyncrasies from set-up-tools.sh (big boost to DRYness and maintainability)

Extra changes included

Trimmed redundant docs

The following documentation/Markdown files were removed due to simply being extra work to maintain while providing no tangible benefit:

• Supplementary detailed guides for agents on available MCP tools, both per-category and per-MCP (these were never needed by agents in practice)
• READMEs and extra legacy docs in tools/ and agents/

Fix obsolete paths in agent role prompts

• Paths in claude-subagents/ and role-prompts/ agent role definition files were updated to point to the appropriate files in protocols/context/static/