fix(miner-ui): keep mobile chat sheet mounted so conversation state survives (#7792)

[kai392]

Summary

• Mobile ChatRail uses forceMount so chat state survives sheet close/reopen (matches desktop).
• SheetContent forwards forceMount to Portal + Overlay + Content (Content-only is insufficient).
• Regression test: draft text survives mobile close/reopen.

Closes #7792

Test plan

• vitest run src/chat-rail.test.tsx — 7/7 pass
• eslint clean on changed miner-ui files (prettier LF)
• CI validate-code

[superagent-security]

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

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Tip

✅ LoopOver review result - approve/merge recommended

_{Review updated: 2026-07-21 16:07:47 UTC}

3 files · 1 AI reviewer · no blockers · readiness 98/100 · CI green · clean

✅ Suggested Action - Approve/Merge

• safe to merge

Review summary
This fixes a real bug: the mobile chat sheet was unmounting `RailBody`/`ChatConversation` on close, losing draft/conversation state, while the desktop docked panel preserved it via `hidden` instead of unmounting. The fix correctly forwards `forceMount` through `SheetPortal`, `SheetOverlay`, and `SheetPrimitive.Content` together (not just Content, which would be a no-op since Radix's Portal Presence gates the whole subtree), and the regression test exercises the actual close/reopen cycle via a stateful mock rather than a fabricated scenario. The change is narrow, well-targeted at #7792, and the reasoning in the code comments matches the underlying Radix Presence behavior.

Nits — 5 non-blocking

• apps/loopover-miner-ui/src/components/chat-rail.tsx:51 — the `Chat conversation state is lost on mobile every time the chat sheet is closed, contradicting the component's own documented intent #7792` reference in the comment is fine as an issue pointer, not a magic number needing a named constant; no action needed.
• packages/loopover-ui-kit/src/components/sheet.tsx:78 — since `SheetOverlay` is unconditionally force-mounted whenever any caller passes `forceMount`, verify the overlay's CSS (opacity/pointer-events tied to `data-[state]`) fully hides it when closed so it doesn't intercept clicks or show a stray backdrop while off-screen.
• The test at chat-rail.test.tsx:106 uses `getByRole('dialog', { hidden: true })` to assert continued presence, which is correct, but consider also asserting `aria-hidden`/`data-state="closed"` on the dialog to guard against the overlay remaining interactive.
• Consider adding a brief inline test or assertion in sheet.tsx (or a ui-kit level test) that a sheet without `forceMount` still fully unmounts on close, to guard the 'every other sheet' claim in the comment against future regressions.
• apps/loopover-miner-ui/src/components/chat-rail.tsx docked-panel comment references 'any future in-rail state' — since RailBody now also force-mounts identically for both mobile and desktop, this comment could be tightened to say both paths now share the same never-unmount contract.

Decision drivers

• ✅ Code review — No blockers (1 reviewer)
• ✅ Gate result — Passing (No configured blocker found.)

Context & advisory signals — never blocks the verdict

Signal	Result	Evidence
Linked issue	✅ Linked	#7792
Related work	✅ No active overlap found	No same-issue or scoped active PR overlap found.
Change scope	✅ 20/20	Low review scope from cached public metadata (1 linked issue).
Validation posture	✅ 25/25	PR body includes validation/test evidence.
Contributor workload	✅ 10/10	Author activity: 39 registered-repo PR(s), 24 merged, 0 issue(s).
Contributor context	✅ Confirmed Gittensor contributor	kai392; Gittensor profile; 39 PR(s), 0 issue(s).
Improvement	✅ Minor	risk: clean · value: minor · LLM: moderate

Linked issue satisfaction

Addressed
The PR forwards forceMount through SheetPortal/SheetOverlay/SheetContent and passes it from chat-rail's mobile Sheet, directly implementing the issue's recommended fix so RailBody stays mounted across close/reopen; it also adds the requested regression test asserting draft state survives a mobile sheet close/reopen cycle.

Review context

• Author: kai392
• Role context: outside_contributor
• Public audience mode: oss maintainer
• Lane context: Repository is configured for direct PR review.
• Public profile languages: JavaScript, Kotlin, Perl, TypeScript, Vue
• Official Gittensor activity: 39 PR(s), 0 issue(s).
• PR-specific overlap: none found.

Contributor next steps

• Keep the PR focused and include validation evidence before maintainer review.

Signal definitions

• Related work = same linked issue, overlapping active PRs, or title/path similarity.
• Change scope = cached public metadata such as size labels, draft state, and review-burden hints.
• Validation posture = whether the PR provides enough public validation/test evidence for maintainer review.
• Contributor workload = public contributor activity and cleanup pressure, not a repo-wide quality failure.
• Contributor context = public GitHub/Gittensor identity context; non-Gittensor status is not a blocker.

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Visual preview

Route	Viewport	Before (production)	After (this PR's preview)	Diff
/	desktop	before /	after /	—
/	mobile	before / (mobile)	after / (mobile)	—

Click any thumbnail to open the full-size screenshot. Before = production · After = this PR's preview deploy.

Scroll preview

Route	Before (production)	After (this PR's preview)
/	before / (scroll)	after / (scroll)

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

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