feat(console): treasury screen onto org-scoped /orgs/:id/treasury

[hitakshiA]

Epic: #58 · Step D (Treasury)

Rewire the console's Treasury screen off its demo-era (Stellar-legacy) endpoints onto the real org-scoped backend. Builds on the cookie-SIWE session (#60) and onboarding (#63, which already provisions the managed treasury).

Backend contract (source of truth — services/api/src/routes/orgs.ts)

GET  /orgs/:id/treasury                → 200 { address, custody:"managed", registered, consented,
                                              custodyConsent:{consented,consentedAt,consentedBy},
                                              balances:[{ token:"usdc"|"eurc", tokenId, symbol, decimals, amount }] }
POST /orgs/:id/treasury/deposit        → 201|202|200 { amount, approvalTxHash?, source:"direct",
       { amount, token:"usdc"|"eurc", idempotencyKey }   status:"confirmed"|"submitted", token, tokenId, txHash }
GET  /orgs/:id/treasury/deposits       → 200 { deposits:[{ id, kind:"direct"|"cctp", amount, token,
       (query: limit?, before?)              status:"pending"|"credited"|"failed", txHash, sourceChain, createdAt, updatedAt }],
                                              nextCursor }

amount in the deposit request is minor units (/^[1-9][0-9]*$/, USDC 6dp). idempotencyKey is required (generate one per attempt). All monetary fields are strings.

Changes

• lib/api.ts — replace the treasury client fns with the org-scoped ones: orgTreasury(orgId) → GET /orgs/:id/treasury; depositToTreasury(orgId, { amount, token, idempotencyKey }) → POST /orgs/:id/treasury/deposit; treasuryDeposits(orgId, { limit?, before? }) → GET /orgs/:id/treasury/deposits. REMOVE the no-backend fns/paths: treasury(GET /treasury), treasuryPublicBalance, treasuryReceive, treasurySendPublic, fundTreasury, proveBalance, proveTotal, proveSolvency (and their /treasury/* paths).
• lib/store.tsx — the treasury read model is now org-scoped: only fetch it when session.activeOrg exists, calling api.orgTreasury(activeOrg.id). Keep the independent-read resilience (don't blank on a transient miss).
• screens/Treasury.tsx — render the real treasury: the managed treasury address, registered status, and the per-token encrypted balances. Primary action = Add funds → depositToTreasury (direct ERC20 → encrypted balance) with a generated idempotencyKey, reflecting status (submitted vs confirmed) + the tx. Show recent deposits from treasuryDeposits (kind/amount/status/tx). REMOVE from real mode the actions with no backend (public balance, receive/QR, send-to-wallet, prove-balance/total/solvency). Money shown in USDC (6dp) via the existing formatters.
• packages/types — treasury view + deposit + deposits-history response types matching the backend (drop the Stellar-legacy stroops/issuer shapes for real mode).
• Demo — update demo/api.ts/demo/data.ts treasury stubs to the new shapes so VITE_DEMO_MODE=1 still renders a populated Treasury screen.

Out of scope

Cross-chain CCTP funding (/orgs/:id/treasury/fund-intent) — leave a clear TODO seam but don't build the CCTP UX in this PR. Payroll (E), hiding no-backend screens (B).

Definition of done — run ALL, make them pass:

pnpm --filter @benzo/console typecheck · test · build · VITE_DEMO_MODE=1 … build · pnpm exec biome lint .

Operating rules

No git (can't commit). Match the codebase style. End with (1) a one-line conventional-commit message and (2) the exact git add <paths> list.