feature: translate COACTUPC account update transaction to Spring Boot service

[devin-ai-integration]

Summary

Adds java/coactupc-service/, a Spring Boot 2.7 (Java 11) module that re-implements the CICS transaction CAUP / program COACTUPC (account + customer update) with the same business rules, and documents the translation in docs/COACTUPC-field-mapping.md.

Shape of the translation

• Copybooks → JPA entities, PIC widths preserved as column widths/precision: CVACT01Y→AccountRecord, CVCUS01Y→CustomerRecord, CVACT03Y→CardXrefRecord (the CXACAIX alternate index becomes findFirstByAcctId). S9(10)V99 → BigDecimal(12,2); X(10) dates stay YYYY-MM-DD strings. FILLER dropped.
• ACUP-OLD/NEW-DETAILS (the COMMAREA screen snapshot) → AccountUpdateDetails, all-String fields with dates split Y/M/D, SSN split 3/2/4, phones split (AAA)BBB-CCCC, exactly as the COBOL stores them.
• Paragraphs → methods on AccountUpdateService / FieldEditor (1200-EDIT-MAP-INPUTS→editMapInputs, 1205-COMPARE-OLD-NEW→compareOldNew, 9600-WRITE-PROCESSING→writeProcessing, 1220-EDIT-YESNO→editYesNo, …). Edit order, first-error-wins (WS-RETURN-MSG-OFF) semantics, per-field VALID/NOT_OK/BLANK flags, and message literals are preserved. CSLKPCDY lookup lists (general-purpose area codes, state codes, state+zip2 combos) are generated into lookup/*.
• ACUP-CHANGE-ACTION → ChangeAction enum (S/E/N/C/L/F); WS-INFO-MSG/WS-RETURN-MSG 88s → Messages.
• CICS → Spring: READ→findById, READ UPDATE→@Lock(PESSIMISTIC_WRITE), 9700-CHECK-CHANGE-IN-REC optimistic check → DATA_CHANGED, REWRITE×2 + SYNCPOINT ROLLBACK → one @Transactional method.

HTTP surface (AccountUpdateController)

GET  /api/v1/accounts/{id}            fetch (ENTER on search)  200 | 400 bad id | 404 xref/acct/cust not found
POST /api/v1/accounts/{id}/validate   ENTER with edits         200 always: NO_CHANGE / CHANGES_NOT_OK / CHANGES_OK_NOT_CONFIRMED
PUT  /api/v1/accounts/{id}            PF5 save                 200 done | 409 record changed underneath | 423 lock | 500 rewrite failed

PF3/PF12 are pure navigation (PF12 = client re-issues GET) and are documented rather than implemented.

Deliberate deviations (all in doc §7)

• ACCT-UPDATE-RECORD in the COBOL omits ACCT-ADDR-ZIP, so ACCT-UPDATE-GROUP-ID lands at offset 102 — the REWRITE overwrites the zip with the group id and blanks the real group id. The Java writes groupId to the right column and leaves addrZip untouched (intent-preserving, defect not reproduced).
• Money values with >10 integer digits are rejected ("is not valid") instead of silently truncated by MOVE.
• RESP/RESP2 codes are not echoed in not-found messages; the WS-RETURN-MSG 88 texts are used.
• 999 is accepted as an area code because it is present in the copybook's VALID-GENERAL-PURP-CODE list.

Tests: 76 JUnit 5 tests — CobolNumericTest (NUMVAL-C), FieldEditorTest (each edit paragraph incl. century/leap-year/DOB rules), AccountUpdateServiceTest (H2: fetch, not-found paths, no-change, first-error ordering, confirm+persist formats, stale-record 409, lock errors), AccountUpdateControllerTest (status mapping).

Run: cd java/coactupc-service && mvn test

Devin-Org: engineering

Link to Devin session: https://app.devin.ai/sessions/01a88c7fe88b4a1882290d650c00b721
Open in Devin Desktop: https://app.devin.ai/desktop/session/01a88c7fe88b4a1882290d650c00b721?variant=devin
Requested by: @rushcromer

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Devin errored when opening this Pull Request as rushcromer.
As a fallback, Devin opened this PR as itself.

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