docs: redesign README around benchmark proof

[cyfyifanchen]

Summary

• Reframe the README around benchmark evidence, onboarding, Deep Research, and Tracing.
• Restore the main branch's opening product capability overview before the benchmark evidence.
• Keep the table of contents removed and place the native Markdown benchmark table directly after the introduction.
• Remove outbound links from the three benchmark row labels while preserving the reported results and supporting context.
• Synchronize the English and Chinese READMEs around the same structure, spacing, and Back to top section boundaries.
• Place the GitHub User Content onboarding recording directly below the benchmark table in both READMEs, using the same bare attachment URL.
• Reduce duplicate capability, gateway, status, and ecosystem copy while preserving concise architecture and command references.
• Document current runtime behavior for the six-step onboarding flow, MiroThinker-backed research delivery, and local trace storage.

Type

• Fix
• Feature
• Docs
• CI / tooling
• Refactor
• Other

Verification

• Relevant tests pass locally
• Relevant lint / type checks pass locally
• User-facing docs or screenshots are updated when needed

Commands and results:

• .venv/bin/pre-commit run --files README.md README.zh-CN.md - passed all applicable hooks.
• git diff --check origin/main...HEAD - passed.
• make check-large-files - passed.
• git merge-tree --write-tree HEAD origin/main - passed with no conflicts.
• README structure assertions - passed: no table of contents, no benchmark-label links, and four matching Back to top boundaries in each language.
• Confirmed both READMEs use the same 33378-byte GitHub User Content hero banner; benchmark evidence is native Markdown.
• Confirmed the 1179517-byte onboarding MP4 round-trips from GitHub User Content with SHA-256 124024e6d64c23b3e314aa6136d9e0d922f57ded97a830a5c97cd1323cb2c57f and renders with controls below Benchmarks in both languages.
• uv run pytest --tb=short -q - 6130 passed, 33 skipped, and one local Python 3.14 ANSI color assertion failed; the GitHub Python 3.12 unit job passed.

Risk

• Security impact considered
• Backward compatibility considered
• Rollback path is clear for risky changes

This is a low-risk documentation-only change. Rollback requires reverting the README commits; externally hosted user-content assets can remain unreferenced without affecting repository size.

Related Issues

N/A

[cyfyifanchen]

README benchmark artwork (hosted through GitHub User Content):

[cyfyifanchen]

Optimized README assets (WebP, hosted through GitHub User Content):

Banner: 33,378 bytes

Benchmark: 50,026 bytes

[cyfyifanchen]

Light benchmark variant for the README (WebP, 55,342 bytes, hosted through GitHub User Content):

[cyfyifanchen]

README welcome screen assets (optimized for GitHub User Content):

[cyfyifanchen]

README onboarding video (GitHub User Content, 553,353 bytes):

otty-raven-onboarding.mp4

[cyfyifanchen]

Updated README onboarding video (GitHub User Content, 1,179,517 bytes):

otty-raven-onboarding.mp4