fusion_authorizer_portal: wire accessibility assessments into MOD/ODSP/WSIB workflows (v19.0.2.8.0)

Audit found that fusion.accessibility.assessment._create_draft_sale_order
hardcoded x_fc_sale_type='direct_private' for ALL accessibility cases —
meaning MOD, ODSP, WSIB, and insurance projects never entered their
respective downstream workflows. The MOD workflow rework I shipped in
fusion_claims 19.0.8.0.3 was effectively unreachable from the portal.

Also: x_fc_authorizer_id never propagated from the assessment to the SO,
the new x_fc_mod_accessibility_specialist_id was orphaned, and there
was no back-reference from sale.order to the accessibility assessment.

Fixes:
- New required field x_fc_funding_source on fusion.accessibility.assessment
  (march_of_dimes / odsp / wsib / insurance / direct_private / other)
- _create_draft_sale_order now maps funding_source -> x_fc_sale_type,
  copies authorizer_id -> x_fc_authorizer_id, sets accessibility_assessment_id
  back-ref, and for MOD cases pre-populates
  x_fc_mod_accessibility_specialist_id from sales_rep_id.partner_id
- New accessibility_assessment_id field on sale.order so the back-link
  is queryable both directions (previously only assessment->SO existed)
- action_complete now guards against double-completion and missing
  funding_source: raises UserError instead of silently creating duplicates
- Expanded fusion.accessibility.assessment.state from 3 to 6 values
  (draft/scheduled/in_progress/pending_review/completed/cancelled),
  added copy=False, added _expand_states group_expand for kanban
- Booking form at /book-assessment now collects funding_source
  (required dropdown) so the path is known before the visit happens
- portal_assessment.py book_assessment_submit accepts funding_source
  with whitelist validation (defaults to direct_private if missing)

Deployed to odoo-westin (westin-v19) and odoo-mobility (mobility),
both verified at v19.0.2.8.0 with the new columns present.

fusion_authorizer_portal/views/portal_book_assessment.xml

@@ -45,6 +45,25 @@
                                 </select>
                             </div>
 
+                            <!-- Funding Source (2026-04 portal audit fix —
+                                 required so the generated sale order enters
+                                 the correct downstream workflow: MOD, ODSP, etc) -->
+                            <div class="mb-3">
+                                <label class="form-label fw-bold">How is this project being funded?<span class="text-danger"> *</span></label>
+                                <select name="funding_source" class="form-select" required="">
+                                    <option value="">Select...</option>
+                                    <option value="march_of_dimes">March of Dimes</option>
+                                    <option value="odsp">ODSP</option>
+                                    <option value="wsib">WSIB</option>
+                                    <option value="insurance">Private Insurance</option>
+                                    <option value="direct_private">Private Pay (Direct)</option>
+                                    <option value="other">Other</option>
+                                </select>
+                                <small class="form-text text-muted">
+                                    This determines which workflow the case enters after the visit.
+                                </small>
+                            </div>
+
                             <div class="mb-3">
                                 <label class="form-label fw-bold">What are you looking for?</label>
                                 <textarea name="modification_requested" class="form-control" rows="2"