README: rewrite as general reference (not progress journal)

The README had drifted into a per-week progress log: "validated this
week", "what's also new this week", a 30-line status table that read
like a changelog. With v0.0.2 through v0.2 now tagged as GitHub
Releases carrying chapter-by-chapter summaries, the README's job is
to be the stable entry point for both human and LLM readers.

Structural changes:
- Drops the "this week" framing entirely (that lives in releases now)
- New top-level sections: Why OMC, Installation, Quick start,
  Capabilities, Use cases, LLM integration, Documentation map,
  Reading the project's history, Repository layout, CLI reference,
  Status, Contributing
- Installation: prerequisites + from-source + JIT + WASM/LSP/Godot/Python
- Quick start: hello.omc using the new Python-idiom features
- Capabilities: bullets by area (language / substrate primitives /
  Prometheus / infrastructure), not a 30-line journal
- Use cases: concrete things people build (ML research, anomaly
  detection, code archaeology, multi-agent systems, ...)
- LLM integration: MCP server, codec, did-you-mean, substrate
  tokenizer, omc_explain_error — first-class for LLM consumption
- Documentation map: pointers into docs/ and per-subsystem READMEs
- Reading order: anchors to GitHub Releases (was pointing at
  CHANGELOG sections only)
- Status: replaced 30-line table with terse summary + per-chapter
  reference
- Contributing: PR checklist

Also updates GitHub repo About + topics:
- Description: emphasizes the language + substrate-attention win
- Homepage points at README anchor
- Topics: drop "code"/"new"/"experimental" (filler); add
  substrate-computing, llm-tooling, mcp-server, transformer,
  golden-ratio, dual-band (signal)

The journal-style scoreboards and "ALSO this week" content are
preserved per-chapter in CHANGELOG.md and the matching release
notes — no information lost, just relocated to where it belongs.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: RandomCoder-lab