fix(jira): correct Data Sensitivity field ID and replicate Jira's real classification scheme

The auto-create-ticket call was sending customfield_11233 (a field that
doesn't exist in the project) instead of the real Data Sensitivity field
customfield_11814, which made Jira reject the WHOLE issue and silently
block ticket creation for every new test.

Also replaces Aegis's invented 4-tier data_classification scheme
(public_release/general_use/confidential/restricted) with the 6 values
Jira's Data Sensitivity field actually uses (public/general_use/
internal_use_only/trusted_people/customer_content/pii), since that is
the classification the organization actually applies. Includes a data
migration remapping existing rows and a defensive retry if Jira ever
rejects an unscreened custom field again.

backend/app/domain/enums.py

@@ -93,14 +93,19 @@ class AttackSuccessResult(str, enum.Enum):
 class DataClassification(str, enum.Enum):
     """Data sensitivity classification levels for compliance and retention policies.
 
-    Matches the organization's data protection scheme:
-    - public_release: approved for external/public release
+    Matches Jira's "Data Sensitivity" field (customfield_11814) exactly, since
+    that is the organization's actual data protection scheme:
+    - public: approved for external/public release
     - general_use: general internal information, no special restriction
-    - confidential: internal use only, or shared with trusted people
-    - restricted: trusted people, customer content, and/or PII
+    - internal_use_only: internal use only
+    - trusted_people: shared only with a limited/trusted audience
+    - customer_content: contains customer data
+    - pii: contains personally identifiable information
     """
 
-    public_release = "public_release"
+    public = "public"
     general_use = "general_use"
-    confidential = "confidential"
-    restricted = "restricted"
+    internal_use_only = "internal_use_only"
+    trusted_people = "trusted_people"
+    customer_content = "customer_content"
+    pii = "pii"