docs(campaigns): document phase 1 campaign management

Records what Phase 1 does and deliberately does not do: no Meta writes, no
launch or sync endpoint, previews rendered without creating objects, budget
minimums enforced locally, and the fact that a payment method can only be
attached in Meta Business Manager.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -57,6 +57,49 @@ npm run local:import-json                # perform the import
 The import upserts by id and never deletes, so it is safe to re-run. The JSON
 files are left untouched as a backup.
 
+## Campaigns
+
+Campaign records live in PostgreSQL. Apply the schema before first use:
+
+```powershell
+npm run local:migrate
+```
+
+Set `META_ADS_ACCESS_TOKEN` in Settings > Environments, and enable the
+`meta_ads` MCP client if you also want campaign tools in chat.
+
+### What Phase 1 does and does not do
+
+Phase 1 owns campaign records, the approval workflow, budget guardrails and ad
+preview. **It creates nothing in Meta.** The only Meta calls are two reads:
+
+- `GET /act_<id>` for balance, spend and `min_daily_budget`
+- `GET /act_<id>/generatepreviews` to render ad previews
+
+There is deliberately no launch or sync endpoint. A campaign moves
+`draft -> pending_approval -> approved` and stops there; pushing objects to
+Meta arrives in Phase 2.
+
+Ad previews are rendered from a creative spec and create no Meta objects, so
+the wizard can show exactly how an ad will look across desktop feed, mobile
+feed, Instagram feed, Instagram story, Facebook story and right column before
+anything exists.
+
+### Budget minimums
+
+Each ad account publishes a `min_daily_budget` in minor units. The API rejects
+a lower daily budget with `422` and a readable message rather than letting Meta
+reject it opaquely later. If the account cannot be read (no token, rate limit),
+the check is skipped and a warning is logged: the budget guardrail is not
+enforced in that case.
+
+### Delivery requires a payment method
+
+Meta will not deliver ads until a funding source is attached to the ad account.
+**This cannot be done from MaskanX** — the Marketing API does not allow
+creating funding instruments, so it must be done in Meta Business Manager. The
+Campaigns page shows a warning when no payment method is present.
+
 ### Clearing and restoring credentials
 
 **Stop MaskanX before clearing credentials.** A running app holds its