Campaign Applications (Flipped Discovery)

Before today, advertisers had three push mechanisms (briefs, marketplace bids, opportunity EOIs). SOURCEs had one real pull mechanism (post a listing, wait). This release flips the marketplace — advertisers broadcast demand, creators apply to match. It's the largest structural change to the sourcing funnel since the platform launched.

Migration a2b3c4d5e6f7 adds:

• 10 nullable columns to campaigns (publishing toggle, deadline, eligibility criteria, per-creator budget range)
• campaign_applications table with polymorphic FK to creator workspace + user, snapshot fields (follower count / platform / niches frozen at apply time), match_score cache, status FSM as VARCHAR(20) (matches SchedulingDeal pattern)
• 6 indexes including partial unique (campaign_id, creator_workspace_id) WHERE status IN ('pending','shortlisted','accepted')

Migration b3c4d5e6f7a8 seeds 5 campaign_application.* IN_APP notification templates.

| Endpoint | Role | Purpose | |---|---|---| | PATCH /campaigns/{id}/publish-applications | ADV, AGENCY | Toggle + eligibility + deadline | | GET /campaigns/feed/applications | SOURCE, SA | Paginated feed with best_fit sort, my_match dots, my_application_status | | POST /campaigns/{id}/applications | SOURCE | Submit pitch + rate + availability + sample URLs | | GET /campaigns/{id}/applications | ADV owner, SA | Advertiser inbox with score/newest/rate/rating sort | | GET /applications/mine | SOURCE | Own apps with status filter | | PATCH /applications/{id} | ADV (shortlist/decline/accept), SOURCE (withdraw) | Single dispatcher; accept spawns SchedulingDeal | | GET /applications/{id} | ADV, SOURCE, SA | Detail |

Self-protection at apply time:

• Max 5 active applications globally per creator
• Unique active per (campaign, creator) enforced by partial unique index
• Restriction guard reused from existing marketplace/scheduling flows
• Reputation: ≥1 completed deal + avg rating ≥4.0 — with new-creator exception (first 3 lifetime apps allowed without the gate)
• SA cannot create workspace-scoped things (matches CLAUDE.md rule)

Match score formula (pure, 0–100): `` 0.40 × (rating/5) + 0.30 × eligibility_match_ratio + 0.20 × budget_fit(proposed_rate, campaign_range) + 0.10 × (0 if has_restriction_conflict else 1) ``

Persisted at create time using the rating already fetched in the reputation gate — no duplicate query. Inbox recomputes on-the-fly for null rows without persisting (read-path side effect avoided).

Accept → SchedulingDeal: wraps row in SELECT ... FOR UPDATE, creates deal with snapshotted pitch as notes and proposed_rate as agreed_price. Creator gets HIGH-priority accepted notification with deal_id in the action URL.

Notifications reuse the existing emit_event + group_key pattern from deal_chat: advertiser gets a grouped submitted notification (60-min coalescing) when applications land; creator gets direct notifications for shortlist/accept/decline/expire.

Expiry scan wired into the existing SA cron (POST /admin/analytics/run-scheduled). Flips pending/shortlisted → expired when past deadline or >30 days old. Nightly basis, not Celery.

• /opportunities/campaigns — feed with sort pills (Best fit / Newest / Deadline soon) + niche + platform + min-budget filters. Each card shows 5 eligibility dots and an Applied/Shortlisted badge if the creator already applied.
• /opportunities/campaigns/[id] — single-campaign detail with full eligibility checklist, my-application status banner, and a gated Apply CTA.
• /opportunities/applications — My Applications list with status filter pills, View/Withdraw/Open Deal actions per card.
• ApplyToCampaignModal — property auto-selector, rate pre-fill from rate card, 50-2000 char pitch with live counter, up to 10 sample URLs, friendly error surfacing for all 4 rejection codes.
• Sidebar: new Campaign Feed + My Applications entries for SOURCE, gated by INFLUENCER|PUBLISHER mode.

• EligibilityForm — reusable block (toggle, deadline, follower range, budget range, niches chip picker, locations chip input, platforms multi-select) with inline validation warnings.
• /campaigns/[id]/edit — new "Creator Applications" section mounting the form; save delta-detects the eligibility section and calls publish-applications only when dirty.
• /campaigns/[id]/applications — new Applications tab as a nested route (matches existing /adplan, /audience pattern). Inbox has sort pills, status filter, 10-sec poll, empty + closed-campaign banners.
• ApplicationRow — avatar + pitch (3-line clamp) + eligibility dots + colored match-score badge + restriction-conflict pill + shortlist/decline/accept buttons with inline decline-reason textarea + status pill + Open Deal link when accepted.
• _serialize_campaign extended to emit the 10 new fields so the edit form pre-fills.

| Role | Publish | Browse feed | Apply | View inbox | Shortlist/Accept/Decline | Withdraw | |---|---|---|---|---|---|---| | ADVERTISER (owner) | ✓ | | | own campaigns | ✓ | | | AGENCY_ADMIN | ✓ | | | own tenant's | ✓ | | | SOURCE | | ✓ | ✓ | | | own only | | VENDOR | | | | | | | | SA | (observes) | cross-tenant | ✗ (workspace-scoped) | cross-tenant | ✗ | |

• ADV publishes a campaign → SOURCE feed shows it with green eligibility dots
• SOURCE applies → ADV inbox count increments, grouped notification fires
• ADV shortlists → SOURCE notification + status badge updates
• ADV accepts → SchedulingDeal row created, deal page loads, deal_chat works, HIGH-priority notification to creator
• SA reads feed + inbox cross-tenant, cannot mutate (explicit 400)
• Restriction guard fires at apply time (not just at deal creation) — creators don't get false hope
• Feature flag disable → all new endpoints return 403

• Typing indicator on inbox
• Fine-grained per-user read receipts (workspace-level only today)
• Auto-matching ML / recommendation engine (simple score formula is sufficient)
• Dedicated application-only chat thread (deal_chat spawns lazily after accept — no separate thread)
• Bulk apply or bulk accept (one at a time)
• Application revisions (withdraw + re-apply instead)
• Public campaigns visible to logged-out users (auth required)
• Pixel-level conversion tracking tied to applications (see separate "Trackable Links" proposal — not in this release)

---