fix(#198): commit-on-success streaming for the detached Data view

[BorisTyshkevich]

What & why

Fixes #198. In the detached Data view, changing a filter or clicking Refresh reran the captured query through the shared streaming seam and repainted the in-flight result on every network chunk. Two visible problems:

1. Empty-result flash — a chunk can carry column metadata before any data rows (columns.length > 0, rows.length === 0), so the shared renderer momentarily showed Query returned 0 rows. even though rows arrived on the next chunk.
2. Chart churn — on Panel, every chunk destroyed the current Chart.js instance and built a new one.

This adopts the same commit-on-success UI policy already used for dashboard tiles (#193).

Change (src/ui/results.js)

• onChunk is now progress-only: Running… <n> rows read (else Running…). It never calls paint() and never touches current / statEl / view / sort / widths / panelState / chartInstance.
• Start state shows Running… and disables Refresh.
• After runReadInto() (current generation only): cancelled → settle(''), error → settle(err), else commit current = result, record bound params once, settle(''), paint() — exactly one repaint.
• Removed the failure-time paint(current) restore: the in-flight result is never painted, so the committed result is already on screen on every non-success path.

Everything else (parameter analysis, prepared batch, token preflight, captured session, generation guard, AbortController, success-only recent recording) is unchanged. No generic "refreshable surface" abstraction introduced — detached and dashboard presentation semantics stay distinct, per the issue.

Tests (tests/unit/results.test.js)

New coverage via a controllable runReadInto seam: previous-result retention through a metadata-only chunk + a data chunk (no 0 rows flash, committed count unchanged, status text), commit-once Copy/recents targeting (old before, new after), no per-chunk chart churn (old chart destroyed once + one replacement on success), current-generation cancellation, and stale-chunk status suppression.

Verification

• npm test — 2353 passed; src/ui/results.js holds the gate (br 95.04 / fn 97.26 / lines 100). npm run build clean.
• Streaming policy is pinned deterministically by the new unit tests; I'll do a live confirmation on otel at deploy time (a slow rerun no longer flashes 0 rows / churns the chart).

Checklist

• Coverage gate holds (100 lines; fn/br within the results.js gate)
• Layers honest — change is confined to the detached view's in-flight presentation policy in src/ui/results.js
• No new runtime dependency
• CHANGELOG [Unreleased] updated
• Reconciled: roadmap Roadmap to 1.0.0 #68 (Detached Data view: keep the committed result visible during streaming reruns #198 follow-up noted under Make the detached Data view interactive: Panel switcher + query filters #185; Dashboard tiles: migrate onto the shared streaming read seam (app.runReadInto) #193 status corrected to merged)

Closes #198

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