docs(ui): audit ui-kit for existing chat-adjacent UI primitives

[galuis116]

Closes #6244

Summary

Research-only groundwork for #6230's eventual chat interface spec (still open). Audits apps/loopover-ui/src/components/** and packages/loopover-ui-kit/src/components/** for anything already resembling the four primitives a chat surface will need — a scrollable message/timeline list, a text composer with submit-on-enter, a streaming/incremental text renderer, and a typing/in-progress indicator — and writes up what's reusable, what's close but needs adaptation, and what's entirely absent. Per the issue's own scope, no functional code changes accompany this: apps/loopover-ui/src/chat-ui-primitives-audit.md is the sole deliverable, following the same design-doc pattern as PR #5794 (#3048).

• Reusable as-is: state-views.tsx's LoadingState/EmptyState/ErrorState/StateBoundary, scroll-area.tsx, avatar.tsx, and the raw textarea.tsx/input.tsx/button.tsx primitives.
• Close but needs adaptation: audit-feed.tsx (filtered, live-fetched list — but table-rendered, not a bubble/timeline layout), command-palette.tsx (the only text-input + filtered-list combo in the app — but click-to-navigate, no Enter-to-submit handling), animated-terminal.tsx (interval-driven typewriter reveal with reduced-motion handling — the closest streaming-text precedent, but over a hardcoded static scene array, not a live stream).
• Entirely absent: a submit-on-Enter composer; any real streaming consumer (grepped apps/loopover-ui/src for EventSource|ReadableStream|text/event-stream|streaming — the one hit is a comment in analytics-proxy.ts explaining why it deliberately avoids a streaming request body); a chat-bubble/message-list component; an inline typing indicator.

Scope

• The PR title follows type(scope): short summary Conventional Commit format.
• This PR is focused and does not mix unrelated backend, UI, MCP, docs, dependency, and deploy changes.
• This follows CONTRIBUTING.md and does not reintroduce GitHub Pages, VitePress, site/, or CNAME.
• I linked a currently open issue this PR resolves — Closes research: audit ui-kit for existing message/chat-adjacent UI primitives #6244.

Validation

• git diff --check
• npm run actionlint
• npm run docs:drift-check
• npm run manifest:drift-check
• npm run command-reference:check
• npm run ui:lint — 0 errors, only pre-existing warnings in unrelated files.
• npm run ui:typecheck / npm run ui:build — both fail identically on a clean main checkout in this sandbox, verified via git stash: ui:typecheck can't resolve the codegen modules collections/browser/collections/server (missing a content-collections build step in this environment), and ui:build can't resolve @scalar/api-reference from @scalar/api-reference-react's dist output. Neither references this PR's new file (apps/loopover-ui/src/chat-ui-primitives-audit.md — a .md file not imported anywhere) and both reproduce byte-for-byte on unmodified main.
• Root npm run typecheck / npm run test:coverage — not run; this sandbox's root typecheck reliably OOMs regardless of diff content (reproduced repeatedly across prior PRs this session via git stash comparison), and this PR has no src/** code changes for Codecov to measure.
• npm audit --audit-level=moderate — 0 vulnerabilities.
• New/changed behavior has tests — N/A, pure documentation addition, no code paths added.

If any required check was skipped, explain why:

• ui:typecheck/ui:build: pre-existing sandbox environment issues (a missing codegen step and an unresolvable third-party subpackage), confirmed unrelated to this diff by reproducing the identical failure on a clean main checkout before and after stashing this PR's single new file.
• Root typecheck/test:coverage: this sandbox's established OOM pattern (unrelated to diff content, confirmed repeatedly this session), and moot here since no src/** files changed.

Safety

• No secrets, wallet details, hotkeys, coldkeys, user PATs, private keys, raw trust scores, private rankings, or private maintainer evidence are exposed.
• Public GitHub text stays sanitized, low-noise, and does not imply compensation guarantees or optimization tactics.
• Auth, cookie, CORS, GitHub App, Cloudflare, or session changes include negative-path tests. — N/A, no such changes.
• API/OpenAPI/MCP behavior is updated and tested where needed. — N/A, no API/MCP surface touched.
• UI changes use live API data or real empty/error/loading states, not production mock/demo fallbacks. — N/A, no UI behavior changed; this only documents existing UI primitives.
• Visible UI changes include a UI Evidence section below with screenshots. — N/A, no visible UI change (a new internal doc file only).
• Public docs/changelogs are updated where needed; changelogs are only edited for release-prep PRs. — CHANGELOG.md untouched.

Notes

• This is the audit/inventory deliverable only, per the issue's explicit instruction ("Do not build anything new — this is a research/audit deliverable only"). Spec: conversational chat interface for loopover (Lovable/Cursor-style) #6230 (the parent chat-interface spec) is still open with its own scope/backend/placement decisions unresolved; this doc is intended to inform that eventual implementation, not to prejudge it.

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

[loopover-orb]

Important

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🔍 LoopOver is reviewing…

AI analysis is in progress. This comment will update when the review is complete.

_{🟩 Safe / merged · 🟦 Advisory · 🟨 Held for review · 🟥 Blocked / closed · 🟪 Reviewing}

[loopover-orb]

LoopOver approves — the gate is satisfied and CI is green.