Experiments Portlet — Screen 2: Create/Update (/experiments/new + /:id/configuration)

Description

Creation is a routed screen, not a dialog: /experiments/new is the Configure screen with an empty draft. This retires the current drawer (name + description only, page implied by the UVE route context) and lets a user create, configure and start an experiment end-to-end without opening the page editor.

Design: approved prototype, edit screen + Select A Page modal + Add Variant modal.

Routing and creation flow

• /experiments/new and /experiments/:experimentId/configuration render the same component in new vs edit mode.
• Autosave is the creation mechanism (design footer: "Changes are saved as you edit." — no Save button): in new mode, debounced autosave issues the POST as soon as name + page exist, then replaceUrl to /experiments/:id/configuration; every subsequent change is a debounced PATCH per field group. Hard dependency on #36988's PATCH fix — without it every autosave call creates an empty Rule.
• Page preselection via query param: /experiments/new?pageId=<uuid> or /experiments/new?url=/index (path resolved by HTMLPAGE search on the current site) prefills the Page card and skips the picker. Invalid param → inline message, never a blank screen. (?page= avoided — collides with pagination; ?url= matches UVE.)
• Locked state when status ∈ {RUNNING, ENDED, ARCHIVED}: banner per the design, every field disabled, add/delete variant hidden; RUNNING copy differs from generic read-only copy.

Layout

Fixed header (back · title falling back to "New Experiment" · status tag · subline {pageTitle} · {pagePath} or "No Page selected" · View Results / Stop when applicable) + scrolling card body (max-width 1040 centered) + pinned footer (hint · Back To Experiments · primary Start/Schedule). Header kebab with end / abort / cancelSchedule / pushPublish / addToBundle gated by AllowedActionsByExperimentStatus (parity with the current screen's menu).

The five cards

1. Details — name (required) + description textarea.
2. Goal — SET/REQUIRED chip; goal name; 4 types as radio cards (BOUNCE_RATE, EXIT_RATE, REACH_PAGE, URL_PARAMETER); condition sub-panels for REACH_PAGE (Parameter/Operator/Value) and URL_PARAMETER (Parameter Name/Operator incl. EXISTS/Value). Operator lists come from what the backend validates after #36988 — never offer an operator the backend silently ignores.
3. Page — read-only summary + Select → Select A Page dialog (900×560: folder tree + page table Page | Template | Modified | State + search, radio selection). A page may host any number of experiments, so the picker restricts nothing: ExperimentsAPIImpl.save puts no page-based condition on creating one. What cannot happen is two running on the same page at once, which start rejects — outright for an immediate start, and for a scheduled one unless the running experiment's window closes before the new one opens. Traffic allocation: slider 1–100 synced with number input.
4. Variants — color dot, name + CONTROL chip, meta line, weight input, delete (non-control, unlocked). Ported parity behaviors: inplace variant rename, copy-variant-URL (dot-copy-button with &variantName=), n/max counter. Total + Split Evenly (even = floor(100/n), first absorbs remainder) + + Add Variant dialog (440px, Variant {n} fallback, re-splits evenly) + warning bar when weights ≠ 100. Edit Content/Preview out of scope here (UVE-integration issue) — render disabled with tooltip or omit until it lands. Cap: whatever #36988 enforces.
5. Scheduling — start/end with time-of-day (p-datepicker [showTime]="true") and the min/max duration bounds from DotExperimentsConfigResolver (the design draws bare date inputs; dropping time + duration validation would be a parity regression). Note box + Clear Schedule.

Validation and transitions

The 8 rules (name, page, goal type, goal name, condition value, parameter name, ≥2 variants, weights = 100), revealed only after pressing Start — scroll to the first [data-error], count in the footer; Start never disabled. Start with date → SCHEDULED; without → RUNNING; Stop → ENDED. Toast per transition.

Store

Signal Store Events, same shape as #36989: experiments-form.events.ts, reducers per card, autosave in withEventHandlers (debounce + switchMap; failed PATCH → DotHttpErrorManagerService, state back to loaded).

Unhide from Screen 1

The New Experiment button and the Configure primary row action in #36989 route here.

Acceptance Criteria

• /experiments/new renders the empty-draft Configure screen; typing a name and picking a page creates the experiment (one POST, no dialog) and the URL becomes /experiments/:id/configuration via replaceUrl.
• Every field change persists via debounced PATCH; no PATCH creates a Rule/ConditionGroup (spec asserts untouched targetingConditions is omitted from the payload).
• ?url=/index and ?pageId=<id> prefill the Page card; invalid values show a message.
• All five cards match the design, including the ported behaviors: variant inplace rename, copy-variant-URL, n/max counter, scheduling time + duration bounds.
• Select A Page: current-site browse, search, radio selection; selection updates the summary + traffic helper copy. No page is excluded or greyed — concurrency on a page is enforced at Start, not at the pick.
• The 8 validation rules reveal on Start, scroll to the first error, count in the footer.
• Start/Schedule/Stop transitions with toasts; locked states disable everything with the right banner copy.
• Header kebab per AllowedActionsByExperimentStatus.
• The old UVE configuration screen is untouched.
• Jest specs per card + the autosave store (fake timers for debounce).

Priority

High.

Additional Context

• Depends on: #36989 (base + list), #36988 (PATCH fix — hard blocker for autosave).
• Out of scope: the variant Edit Content UVE round-trip (own issue); the Targeting card (current one is commented out Hide until is implemented — not a parity loss); autosave conflict resolution beyond last-write-wins.
• Logic to lift (not the ComponentStore shape): validation, weight redistribution and action gating from dot-experiments-configuration/store/dot-experiments-configuration-store.ts.
• E2E (create → configure → start) lives in the dedicated E2E issue.