Update key concepts docs

[kapunahelewong]

Rework the Key Concepts doc for clarity, and translate into all 10 locales

Substantially edits key-concepts.mdx for clarity and readability, then brings all 10 locale translations up to date with the rewrite (they were untouched by this and had drifted out of sync).

Content changes:

• Reverted "The three layers" back to a table (was briefly a Cards grid); converted "Five rules," "The four-area checklist," "Why not call an LLM inline," "Frames," and "Related building blocks" away from Cards/questions into plain lists, bold-headed sections, or tables, since Cards had become overused for content that isn't a navigation grid
• Moved "What Agent Native includes" (renamed from "What you get for free") to sit right after the five rules it depends on, instead of after all the deep-dive sections, and reformatted its 11 bullets into a two-column table
• Added missing context throughout: what the architecture diagram and action fan-out diagram are showing, what the Drizzle schema / db-schema / db-query / useDbSync code samples actually do, how the building-blocks table maps to the file tree above it, and a definition for "contract" on its first use
• Removed every em dash and rhetorical question in the file, rewriting sentences to work without them
• Fixed a real Mermaid syntax bug (parentheses in a node label broke the parser)

Translations:

• Regenerated ar-SA, de-DE, es-ES, fr-FR, hi-IN, ja-JP, ko-KR, pt-BR, zh-CN, zh-TW from scratch against the new English source
• Verified structurally identical to English: same 17 heading anchors, same component IDs, code blocks byte-for-byte identical including comments
• Along the way, fixed a couple of pre-existing translation bugs unrelated to this rewrite (a mistranslated 'navigation' string literal in Korean, translated view-screen/navigate identifiers in Traditional Chinese that should have stayed untranslated)

Includes a changeset (@agent-native/core: patch).

[github-actions]

Here's a visual recap of what changed:

Open the full interactive recap

Large diff — this recap is a summarized view (top files + schema/API deltas).

[kapunahelewong]

Per Claude:
Only Fast tests lane-2 (and the Fast tests gate reflecting it) is still red, and I've now conclusively proven it's a pre-existing bug on main itself, not caused by our rebase or this PR:

• A new test on main (packages/docs/server/plugins/agent-chat.spec.ts, added by the "Update shared framework apps and template flows" commit we just rebased onto) imports a codegen artifact (.generated/actions-registry.ts) that's only ever produced when Vite actually boots — vitest run alone never triggers it.
• I confirmed this by checking out a completely clean worktree of upstream/main at its current tip, with no prior build/dev run, and running that spec file directly: same ERR_MODULE_NOT_FOUND error, 100% reproducible, nothing to do with our PR or the rebase.

[builder-io-integration]

Builder reviewed your changes and has a few items to flag 🟡

Review Details

Incremental Code Review Summary

The latest PR head remains a documentation-only rewrite with ten regenerated locales and a small Hindi translation correction. Most structural checks pass: MDX components, code/Mermaid fences, anchors, links, formatting, and the Core changeset are valid.

Key Findings

• 🟡 MEDIUM — The French four-area checklist reverses the source contract, stating that a UI feature without a corresponding action is invisible to users. The source says a feature with only actions is invisible to users; the French wording should be corrected.
• ⚪ LOW — The rewritten Related building blocks section drops the existing Data Programs documentation link from the English and locale pages, reducing navigation coverage.

Risk remains low because this PR changes documentation and a patch changeset only.

🧪 Browser testing: Will run after this review (PR touches rendered documentation/UI surfaces).