[1.8] Generator data contract: pass ip_client_meta and ip_invoice_meta to all generators

[nielsdrost7]

Target repository: InvoicePlane-e-invoices · branch develop
Related feature issues: #13 · #15
Required by: #16, #17, #18, #19, #20, #21

Problem

New v1.8.0 fields are split across two storage layers:

• Standard columns (client_peppol_id, client_company_number) — already present on the $client object, no change needed
• Meta key→value pairs (client_einvoice_sdi_code, client_einvoice_pec_email, invoice_routing_code_1/2/3) — stored in ip_client_meta / ip_invoice_meta, not on the main objects

Generators currently receive $client and $invoice objects only. They have no way to access meta values. This must be solved before any generator can implement SdI/PEC routing (#19) or routing codes (#16, #17, #20).

What to do

1. E-invoicing controller (main app) — load meta before generator call

Before calling any generator, load both meta arrays:

$client_meta_rows = $this->db->get_where('ip_client_meta', ['client_id' => $client->client_id])->result();
$client_meta = array_column($client_meta_rows, 'meta_value', 'meta_key');

$invoice_meta_rows = $this->db->get_where('ip_invoice_meta', ['invoice_id' => $invoice->invoice_id])->result();
$invoice_meta = array_column($invoice_meta_rows, 'meta_value', 'meta_key');

Pass both arrays to the generator constructor or a new setMeta() method.

2. BaseXml — store meta as properties

Add $client_meta and $invoice_meta as protected properties on BaseXml so every subclass can access them:

protected array $client_meta  = [];
protected array $invoice_meta = [];

3. Safe access pattern (all generators)

$value = $this->client_meta['client_einvoice_sdi_code'] ?? null;
$code1 = $this->invoice_meta['invoice_routing_code_1'] ?? null;
// null-safe — no PHP warning if key absent

Acceptance criteria

• $client_meta and $invoice_meta available in every generator via BaseXml properties
• Missing key access returns null safely — no PHP warnings
• No generator breaks when both meta arrays are empty []
• Existing generators that don't yet use meta fields are unaffected
• The pre-generation validator (see #21) receives the same meta arrays