feat(campaigns): prospect searcher with focused filters + add to sequence

[Rishavraaj]

Summary

Adds a prospect searcher dialog to the Campaign detail page, letting users search Apollo prospects with a focused set of filters and add selected people directly to the sequence. Also introduces a reusable Checkbox primitive to @zuko/ui-kit.

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What changed

apps/web — AddContactsDialog

• New AddContactsDialog component (components/Campaigns/AddContactsDialog.tsx)
• Split-panel layout: filter sidebar on the left, results list on the right
• Limited, high-signal filters only:
  • Name — free-text search
  • Job Title — tag input (press Enter or comma to add multiple)
  • Location — tag input (same UX as titles)
  • Company — async autocomplete with debounced Apollo org search
• Each filter section is collapsible with an active-state indicator dot
• Results show avatar, name, title, company, location, and an In CRM / Prospect badge
• Multi-select via checkboxes with a select-all toggle
• Footer shows selection count and an Add to sequence button
• Resets state cleanly on close
• Lazy-loaded (code-split) from CampaignDetail

apps/web — CampaignDetail

• Added Add Contacts button (UserPlusIcon) to the campaign header actions
• Wires the lazy AddContactsDialog with the current sequenceId
• Fixed pre-existing Tailwind v4 class warning (!justify-start → justify-start!)

apps/web — API client & query options

• lib/api/apollo.ts: added apolloProspectsApi with three methods:
  • search(params) → POST /integrations/apollo/prospects/search
  • searchOrgs(name) → GET /integrations/apollo/organizations/search
  • addToSequence(payload) → POST /integrations/apollo/prospects/add-to-sequence
• Added types: ProspectPerson, ProspectsSearchResponse, OrgSearchResult, SearchProspectsParams, AddPeopleToSequencePayload, AddPeopleToSequenceResponse
• server/query-options.ts: added getProspectSearch and getOrgSearch query options (with enabled guards and appropriate staleTime)

libs/ui-kit — Checkbox primitive

• New checkbox.tsx: Catalyst-style Checkbox component built on Headless UI
• Full light/dark theme support via CSS custom properties
• Multi-color support (dark/zinc, blue, green, red, indigo, etc.)
• Supports indeterminate state
• Companion CheckboxField and CheckboxGroup layout wrappers
• Exported from the ui-kit barrel (ui-kit.tsx)

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UI behaviour

State	What the user sees
Dialog opens, no filters set	"Start by selecting a filter" empty state
Filters applied, loading	Spinner + "Searching…"
Filters applied, no results	"No results found" empty state
Results returned	Scrollable prospect list with checkboxes
Prospects selected	Footer shows count; "Add to sequence (N)" button activates
Add succeeds	Toast success, dialog closes and resets
Partial failure (some prospects couldn't be converted to contacts)	Toast warning with count

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What's NOT in this PR (backend — follow-up)

The frontend targets these endpoints which need backend implementation:

• POST /integrations/apollo/prospects/search
• GET /integrations/apollo/organizations/search
• POST /integrations/apollo/prospects/add-to-sequence

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Testing

• Open a campaign detail page → "Add Contacts" button is visible
• Click "Add Contacts" → dialog opens in split-panel layout
• No filters → empty state shown
• Enter a name / title / location → results load after debounce
• Type 2+ chars in Company → autocomplete suggestions appear
• Select individual rows and select-all toggle work correctly
• "Add to sequence" button is disabled until at least one person is selected
• Successful add → toast + dialog closes
• Closing resets all filters and selections
• Light mode and dark mode both render correctly