Multi-entity and org-level token management

# Instructions — Multi-entity and token handling

## ⚠️ Behavior of list_companies depending on token type

| Token type | Number of entities | id | name |
|------------|-----------|-----|------|
| **org-level** | All active entities | ✅ present | ✅ present |
| **company-scoped** | 1 single entity | ✅ present | **❌ null** |

If `company.name=null`: don't display "null" — show "current entity" or use the id instead.

## Step 1 — List the available entities

Call `list_companies` (no parameters).

**With an org-level token**: returns all active entities with id + name.
**With a company-scoped token**: returns 1 entity with id only.

Inspect the response:
- If 1 entity and `name=null` → company-scoped token → continue with this id
- If several entities with name → org-level token → select according to the need

## Step 2 — Select the target entity or entities

**For a single-entity analysis**: choose the entity by name or by currency as needed.

**For a consolidated multi-entity analysis**:
- Iterate over each companyId
- Call the desired tool for each entity
- Combine the results **only after having all results** (never present partial results)

⚠️ Functional currencies vary by entity — **never sum across currencies**.
Use the `functionalAmount` specific to each entity and display them separately, or convert explicitly.

## Step 3 — Available data (real org-level token example)

11 entities on this account, including:
```
B1stUp83     → SPENDESK (EUR)
Hx1N5m87M   → Spendesk Limited (GBP)
pD0gYhOK75T → Spendesk Inc. (USD)
RRbRgeIB7X  → Spendesk GmbH (EUR)
vvdk2xwqvktsjl → Spendesk USD Test (USD)
```

## Step 4 — Consolidated multi-entity analysis (pattern)

```
For each companyId in list_companies.data:
  1. Call spendesk_analyze_spend(companyId, fromDate, toDate, groupBy)
  2. Extract summary.totalAmount (entity's functional currency)
  3. Store result + currency

Display:
  Entity A: X EUR (N payables)
  Entity B: Y GBP (N payables)
  Entity C: Z USD (N payables)
  ⚠️ Consolidated total in EUR = conversion needed (not provided by the MCP)
```

## Edge case: company-scoped token with a companyId already known

If the token is company-scoped, the tools accept an optional `companyId` (auto-filled).
Passing the companyId explicitly is unnecessary but harmless — the token only accesses its own entity anyway.

## Example prompt

- "Show the spend for each entity in the group" → iterate over list_companies + analyze_spend
- "What's the wallet balance for all our subsidiaries?" → iterate over list_companies + get_wallet_summary
- "Compare France vs UK spend" → 2 calls to analyze_spend on B1stUp83 and Hx1N5m87M