fix: scan all snapshots for oldest timestamp in fetchAllWalletData

snapshotsToDaily returns results sorted newest-first, so allSnaps[0] was
the newest timestamp. This caused fetchPrices to compute a near-zero date
range, resulting in $0 values for all but the most recent rows.

Also removed redundant refreshPrices() call from init flow (fetchAllWalletData
already fetches full-range prices). Added table data flow doc to AGENTS.md.

AGENTS.md

@@ -104,6 +104,22 @@ Cross-tab leader election uses `BroadcastChannel("dione_shared_stream")` with a
 - Adding chart data? Update the embedded arrays (`walletCumulData`, etc.) — they are plain JS arrays of `[timestampMs, value]` pairs.
 - `wallets.js` always forces `isVerified: false` on `loadWallets()` — persisted signatures are discarded. Verification must go through `WalletVerifier`.
 
+## Transaction Ledger Table — Data Flow
+
+How the table gets its rows and values:
+
+1. **Fetch:** `fetchAllWalletData()` → `fetchWalletAaveData(address)` hits `/api/v1/portfolio/{address}/base/aave`, returns array of snapshot events.
+2. **Deduplicate:** `snapshotsToDaily(events)` collapses events to one per day (keeps latest `block_timestamp` per day). **Result is sorted newest-first.**
+3. **Store:** Deduplicated snapshots land in `addressSnapshots[address]`.
+4. **Prices:** `fetchPrices(symbols, oldestDateMs)` fetches `/api/v1/prices/{symbol}/history?range=N` where N = days between now and oldest snapshot. **Critical:** you must scan all snapshots for the *lowest* `block_timestamp` to compute the correct range. `snapshots[0]` is the *newest* — never assume the array is oldest-first. The `aavePriceMap` is keyed `[priceSymbol][dateStr] = closePrice`.
+5. **Render:** `renderCombinedTable()` iterates `addressSnapshots`, computes row values:
+   - `getTokenAmount(raw, symbol)` divides by token decimals (cbBTC /1e8, WETH /1e18, USDC /1e6)
+   - `priceForToken(symbol, dateStr)` looks up `aavePriceMap` for the matching date (falls back to nearest prior date)
+   - Each row shows USD = `amount × price` for wallet (cold), collateral, and debt columns
+6. **Filter:** `updateDashboard()` hides/shows rows based on wallet-type and ledger-wallet checkbox filters.
+
+If table rows show `$0` for non-recent dates, check that `aavePriceMap` covers the full historical range — the `fetchPrices()` call must use the *oldest* snapshot timestamp, not the newest.
+
 ## Coding Guidelines
 
 You are an expert senior Web3 frontend engineer specializing in high-scale performance and stateless cryptographic security.

index.html

@@ -1490,7 +1490,12 @@ async function fetchAllWalletData() {
     await Promise.all(promises);
     const allSnaps = Object.values(addressSnapshots).flat();
     if (allSnaps.length > 0) {
-        const oldestTs = new Date(allSnaps[0].block_timestamp).getTime();
+        /* snapshots are sorted newest-first; find the oldest */
+        let oldestTs = Infinity;
+        allSnaps.forEach(s => {
+            const t = new Date(s.block_timestamp).getTime();
+            if (t < oldestTs) oldestTs = t;
+        });
         await fetchPrices(Object.keys(TOKENS), oldestTs);
     }
 }
@@ -1801,10 +1806,9 @@ async function initDashboardGrid() {
         const rawPrices = result.result.XXBTZUSD;
         btcPriceData = rawPrices.map(item => [item[0] * 1000, parseFloat(item[4])]);
 
-        /* Fetch data for all verified wallets */
+        /* Fetch data for all verified wallets (already fetches full-range prices) */
         await fetchAllWalletData();
 
-        await refreshPrices();
         renderCombinedTable();
 
         const cutoff = getOldestTransactionDate();