docs: reposition RTK as agent-agnostic

[FlorianBruniaux]

Summary

• Intro paragraph: clarifies RTK works with any AI coding agent, not Claude-only
• Token Savings header: "Claude Code Session" → "Coding Session"
• Quick Start: two-path structure — any agent first, Claude Code hook second
• How It Works diagram: "Claude" → "Agent" in ASCII art
• Auto-Rewrite Hook: adds "(Claude Code)" qualifier + agent-agnostic framing
• Applied consistently to all 6 language files (EN, FR, ZH, JA, KO, ES)

Side-fixed: version refs 0.27.1 → 0.27.2, module count 57 → 58 (pre-existing drift caught by pre-push hook).

Motivation

RTK is agent-agnostic by design but the README implied Claude Code exclusivity. A non-Claude-Code user should understand RTK works for them within 10 seconds. Claude Code remains the highlighted integration (hook advantage preserved), but without false exclusivity claims.

Test plan

• Read flow: tagline → intro (agent-agnostic) → token savings → quick start (2 paths) → how it works → commands
• Grep for "Claude Code" references that imply RTK is Claude-only (none should remain in intro/hero)
• Verify all 6 language files updated consistently
• Validate-docs passes (confirmed locally)

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR repositions RTK documentation to present the tool as agent-agnostic rather than Claude Code-specific. All 6 language README files (EN, FR, ZH, JA, KO, ES) plus CLAUDE.md and ARCHITECTURE.md are updated consistently. Side-fixes update version references from 0.27.1 → 0.27.2 and the module count from 57 → 58.

Changes:

• Intro paragraphs, token savings headers, Quick Start sections, and How It Works ASCII diagrams across all 6 language README files updated to use agent-neutral language ("Claude" → "Agent", "Claude Code Session" → "Coding Session")
• Quick Start restructured into two paths: direct usage with any agent first, then Claude Code auto-rewrite hook second, with a summary sentence preserving Claude Code as the highlighted integration
• Version references updated to 0.27.2 in CLAUDE.md and ARCHITECTURE.md, and module count updated to 58 in ARCHITECTURE.md

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
README.md	Agent-agnostic intro, Quick Start two-path structure, diagram update, Auto-Rewrite Hook section gets "(Claude Code)" qualifier, version 0.27.2
README_fr.md	French translation matching all agent-agnostic changes
README_zh.md	Chinese translation matching all agent-agnostic changes
README_ja.md	Japanese translation matching all agent-agnostic changes
README_ko.md	Korean translation matching all agent-agnostic changes
README_es.md	Spanish translation matching all agent-agnostic changes
CLAUDE.md	Version reference updated to 0.27.2
ARCHITECTURE.md	Version reference updated to 0.27.2, module count updated to 58

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[KuSh]

Some commands are still Claude Code only:

• cc-economics
• discover
• learn

❯ rtk discover
Error: Claude Code projects directory not found: /home/user/.claude/projects
Make sure Claude Code has been used at least once.

They should be marked as such now that README says it is agent-agnostic