docs(readme): add feature overview matrix, trim Quick Start

[jeff-r2026]

What

Add a Feature Overview table to the README (both languages) and trim redundant Quick Start prose.

Overview matrix

Agents (rows) × resources (columns), rendered as an HTML two-level header table grouping columns into three areas:

• Harness — skills · rules · docs · env · agents · hooks · mcp
• Knowledge Base — learnings · codebase · teamwiki
• Governance — usage · sessions · dashboard

Covers 8 agents (Claude Code, Codex, Cursor, CodeBuddy, OpenCode, WorkBuddy, OpenClaw, Hermes). ✓/— cells are sourced from src/types.ts toolPaths (per-tool support) and src/builtin-hooks.ts (governance = tools with dispatch hooks).

A Git providers line lists the supported hosts: GitHub · GitLab (incl. self-hosted) · CNB · TGit · any private/self-hosted service (from src/providers/registry.ts).

Trims

• Single-repo mode: removed the 5 detail bullets and the trailing commit-summary sentence
• Removed the --inherit-user-scope layered-setup example and the solo-use note
• Removed the recall coverage/ranking detail paragraphs
• Removed the Global options line

Docs sync

• docs/usage-guide.{md,zh-CN.md}: added GitLab + private/self-hosted to the repo-creation line and moved TGit later in provider lists
• README.md / README.zh-CN.md kept in sync

Test Plan

• Both README tables render with matching column counts (13 data cells/row, colspan 7+3+3)
• No stray garbage characters or escaped pipes
• Provider lists consistent across README + usage-guide (TGit last among named hosts)
• Bilingual docs verified in sync

Docs-only change; no code affected.