docs: rewrite README for current project state

[AbdulmalikAlayande]

The README was significantly outdated — it listed guard, costs, and restore as "coming next" features when all three are fully implemented. It also missed the entire alerting overhaul (HMAC signing, severity levels, retry limits, resolution notifications, test/history commands).

Rewritten in OSS style with complete command reference, alerting documentation, architecture diagram, FAQ, and full project structure.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 7150f013-a9a0-4e26-a2d8-2c551e601ff8

📥 Commits

Reviewing files that changed from the base of the PR and between 59d67e3 and f4cb4c4.

📒 Files selected for processing (1)

• README.md

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📝 Walkthrough

Summary by CodeRabbit

• Documentation
  • Restructured README with improved organization and clarity
  • Added comprehensive command reference for all operations
  • Enhanced installation, Quick Start, and feature documentation
  • Expanded architecture overview and operational guidance with detailed examples

Walkthrough

The README.md was comprehensively rewritten to restructure and expand documentation for the soroban-sentinel sentinel daemon. Changes include reformatted branding with a new Features section, expanded CLI command reference with detailed option tables, enhanced alerting specification with webhook and Slack details, improved daemon operation and configuration guides, and refreshed project structure and implementation documentation.

Changes

Documentation Restructuring and Expansion

Layer / File(s)	Summary
Branding, features, and quick start guide README.md	Reformatted header with centered title and revised "Why this exists" narrative. Added "Features" bullet list. Updated "Install" and rewrote "Quick Start" with structured sentinel watch command reference including an options table and example output.
Detailed CLI command reference README.md	Documented all major sentinel commands: sentinel status, sentinel daemon, sentinel alerts subcommands (add/list/remove/test/history), sentinel guard with usage and security modes, sentinel costs, and sentinel restore. Included explicit option requirements and constraints for each.
Alerting specification and architecture overview README.md	Expanded "Alerting" into a full specification covering lifecycle stages, severity rules, webhook JSON format, signing header details with verification code snippet, Slack delivery setup, and retry behavior. Added "How it works" section with architecture diagram and system flow description.
Daemon operations, storage, and configuration README.md	Rewrote operational narrative describing daemon's three-phase cycle (monitor/deliver/auto-extend). Clarified "Storage" with SQLite location and WAL details. Documented database tables and configuration section with example fields and 0600 permission guidance.
Project structure and architecture layers documentation README.md	Expanded "Project Structure" with detailed directory tree. Added "Architecture layers" section mapping Commands, Core, RPC, Alerts, and Database component responsibilities.
Tech stack, testing, FAQ, roadmap, and metadata README.md	Refreshed "Tech Stack" and "Testing" sections with updated lists. Expanded "FAQ" and "Roadmap" with additional content and roadmap items. Updated "Contributing," "License," and "Author" sections.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Poem

A rabbit hops through the docs with glee, 📚
Restructuring prose from leaf to tree—
Quick starts now sparkle, commands shine bright,
Architecture diagrams guide the night,
Sentinel's story, now crystal and right! ✨

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch dev

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_{Comment @coderabbitai help to get the list of available commands and usage tips.}