doc: update Quick Start & Architecture in README

[imbajin]

Overhaul README to improve developer onboarding and documentation. Adds a Table of Contents, Quick Start (TL;DR + detailed Docker, binary, and build-from-source instructions), verification steps, and a Module Map. Expands Features into bullet points and introduces detailed Architecture sections including ASCII and Mermaid diagrams, a deployment comparison table, and module overview. Adds contributor guidance, community/contact info, and ecosystem links. Also updates .serena/project.yml to set project_name and include placeholders for base/default modes, included optional tools, and fixed_tools to enable per-project Serena configuration.

Purpose of the PR

• close #xxx

Main Changes

Verifying these changes

• Trivial rework / code cleanup without any test coverage. (No Need)
• Already covered by existing tests, such as (please modify tests here).
• Need tests and can be verified as follows:
  • xxx

Does this PR potentially affect the following parts?

• Dependencies (add/update license info & regenerate_known_dependencies.sh)
• Modify configurations
• The public API
• Other affects (typed here)
• Nope

Documentation Status

• Doc - TODO
• Doc - Done
• Doc - No Need

[Copilot]

Pull request overview

This PR comprehensively overhauls the README.md to significantly improve developer onboarding and documentation clarity. It transforms the README from a basic introduction into a structured, navigable guide with clear pathways for different user needs (quick start, development, contribution).

Changes:

• Added comprehensive Table of Contents and quick navigation links for easy access to key sections
• Expanded architecture documentation with ASCII diagrams, Mermaid flowcharts, deployment comparison table, and detailed module descriptions
• Restructured Quick Start into three clear options (Docker, Binary, Source) with TL;DR section for fastest path
• Added Module Map for developer navigation and expanded contributor onboarding guidance
• Enhanced Ecosystem, Community, and Contributing sections with better organization and links
• Updated .serena/project.yml with project_name and placeholders for mode configuration

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
README.md	Complete documentation restructure with TOC, enhanced architecture diagrams, detailed quick start options, module navigation map, and improved contributor guidance
.serena/project.yml	Added project_name configuration and documented placeholders for base_modes, default_modes, and fixed_tools to enable per-project Serena customization

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 35.60%. Comparing base (9babe49) to head (1fcfe53).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2947      +/-   ##
============================================
- Coverage     35.61%   35.60%   -0.02%     
  Complexity      333      333              
============================================
  Files           801      801              
  Lines         67533    67533              
  Branches       8780     8780              
============================================
- Hits          24054    24045       -9     
- Misses        40913    40925      +12     
+ Partials       2566     2563       -3     

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