fix(sitemanage): Xlint this-escape service/listener residual (#2999)

[natechadwick-intsof]

Summary

Partial Xlint cleanup for sitemanage residual issue #2999 (parent module issue #2032, monorepo tracker #2200). After DTO this-escape (#2980 / PR #3000), this PR clears the service / listener / register-on-construct this-escape cluster.

Main changes

• Path item services: seed protected rootName in ctors (no overridable setRootName during construction); keep public final setRootName for post-construct use
• Leaf finals: monitors, PSIndexHelper, servlets, PSServletRequestWrapper, PSProxyAssemblyTemplate, PSMergedRegionTree, PSWidgetPackageResolver
• Proxy template: direct field seeds + final setters + private copyBindings
• Justified suppress for intentional publish-to-registry on Spring beans that must stay non-final (@Transactional / CGLIB-friendly): PSPageImportQueue, PSFolderHelper, listeners, page/widget services, expander registry put

Tests

• New PSThisEscapeServiceListenerTest (4): path root seed, proxy seeds, servlet wrapper, finality

Inventory (main-source this-escape)

Metric	Before	After
this-escape (main)	32	4

Residual

DTO/parser this-escape leftovers, serial-field residual, misc Xlint, test-source this-escape: #3061

Test plan

• cd projects/sitemanage && ../../mvnw.cmd clean install — BUILD SUCCESS
• Tests run: 1031, Failures: 0, Errors: 0, Skipped: 125
• PSThisEscapeServiceListenerTest (4) green
• C2: grepped monorepo for extends of newly final types — none (except intentional non-final PSSitePathItemService test subclasses)

Product documentation

• N/A — pure compiler lint tech debt; no operator/user/API surface change

Gates / evidence (C3)

• modules_built: projects/sitemanage
• build_evidence: cd projects/sitemanage && ../../mvnw.cmd clean install → BUILD SUCCESS; Tests run: 1031, Failures: 0, Errors: 0, Skipped: 125
• downstream_checked: C2 greps for extends of newly final types (monitors, IndexHelper, servlets, proxy, merged region tree, package resolver) — no hits; path services left non-final for existing test subclasses

Operator

Operator: Grok: night-issue-prs (model grok-4.5)

Parent: #2032 / #2200
Fixes #2999 (service/listener cluster); residual #3061.

Co-Authored by Grok Build using grok-4.5 with agent main.