List the account-displaying picker rows for the authenticated company.

Returns a flat list of <code>AccountDisplaying</code> rows for every account in the caller's company chart of accounts. Each row represents one selectable combination that a bookkeeper can pick when entering a manual journal line. Tenant and company are derived from the bearer token — there are no tenant or company path parameters.<p><strong>How rows are produced:</strong> For each master account the downstream service checks whether the account carries any linked sub-account definitions (e.g. a bank account linked to specific bank-accounts, a VAT account linked to VAT-rate items). If the account has <em>no</em> sub-account definitions, exactly one bare row is emitted with <code>combinedCode</code> equal to the bare account code (e.g. <code>"3000"</code>), <code>linkType</code> equal to <code>null</code>, and <code>specificationItem</code> equal to <code>null</code>. If the account has one or more sub-account link specifications, one row is emitted per individual sub-account entry, numbered sequentially across <em>all</em> link types with a 0-based counter suffix: <code>"1020-0"</code>, <code>"1020-1"</code>, …</p><p><strong>combinedCode:</strong> <code>"<accountCode>-<i>"</code> when a sub-account exists (e.g. <code>"1020-0"</code>), or the bare account code string (e.g. <code>"3000"</code>) when <code>linkType</code> is <code>null</code>. The suffix index is a flat 0-based counter per account, spanning all link types in declaration order.</p><p><strong>combinedName:</strong> <code>"<accountName> (<subAccountDisplay>)"</code> when a sub-account exists (e.g. <code>"Bank (UBS)"</code>), or the bare account name (e.g. <code>"Bürobedarf"</code>) when <code>linkType</code> is <code>null</code>.</p><p><strong>parentAccount:</strong> the full master account this row belongs to. Always populated, including for bare rows.</p><p><strong>linkType:</strong> the link-type category name (e.g. <code>"BANK"</code>, <code>"CUSTOMER"</code>, <code>"VAT_RATE"</code>). <code>null</code> when the account has no sub-account definitions.</p><p><strong>linkDisplay:</strong> the human-readable label for the link type in the current locale (e.g. <code>"Bank account"</code>). Falls back to the German label when no translation exists for the requested language. <code>null</code> when <code>linkType</code> is <code>null</code>.</p><p><strong>linkOptional:</strong> <code>true</code> when the sub-account selection is optional for the user (link keys are separated by <code>;</code> in the account definition); <code>false</code> when selecting a sub-account is mandatory (link keys separated by <code>,</code>); <code>null</code> when the account has no sub-account definitions.</p><p><strong>specificationItem:</strong> the resolved sub-account entry for this row. Its <code>link</code> field is the URI that must be round-tripped back to the booking endpoint when the user selects this row. Its <code>display</code> field is the human-readable label shown to the bookkeeper (e.g. <code>"UBS"</code>, <code>"8.1 %"</code>). <code>null</code> when <code>linkType</code> is <code>null</code>.</p><p>Row order is stable: accounts are sorted by code ascending (same order as <code>GET /core/v1/accounting/accounts</code>); sub-account rows within each account preserve the link-type declaration order and then the entry order returned by the underlying service.</p>The endpoint is a pure read — idempotent, no side effects. The caller must hold the <code>ACCOUNTING</code> permission on the company in scope.