fix(perc-system): type remaining assembly/jexl maps (#3280)

[natechadwick-intsof]

Summary

PR-sized residual of #3280 / leftover of #3265 / epic #2022: type remaining com.percussion.services.assembly rawtypes/unchecked map usage with real generics.

• Assemblers: drop redundant getBindings() casts on PSHtmlAssembler / PSMarkdownAssembler; extract PSBinaryAssemblerSupport.resolveSys (Map<?,?> reads)
• Work item: PSAssemblyWorkItem.getMetaData uses a live typed $sys.metadata view (PSAssemblyBindingMaps)
• Nav: PSNavHelper.putNavBaseFromVariables + getParams; PSNavonNodeInvocationHandler.copyPropertyMap
• JEXL: PSAssemblerUtils.combine uses Map<String, List<String>>; timers use the live $sys view
• Finder: PSContentFinderBase.find writes $sys.hasMore through the same helper
• Tests: binding maps, binary resolve, nav helpers, jexl combine/timers, metadata write-through

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

Parent: #2022
Fixes: #3280
Related leftover of: #3265

Product documentation

• N/A — pure tech-debt generics / no product behavior, UX, API, or operator-step change

Test plan

1. From system/: ../mvnw.cmd clean install (JDK 21)
2. Focused: ../mvnw.cmd "-Dtest=PSAssemblyBindingMapsTest,PSBinaryAssemblerSupportTest,PSNavHelperTypedTest,PSAssemblerUtilsTypedTest,PSServicesPackageTypedTest" test
3. Confirm BUILD SUCCESS and new/updated tests green

Checklist

• Product documentation — N/A (not product-facing): pure tech-debt generics
• Unit / module tests — new/extended unit tests; system standalone mvnw clean install green
• WebUI + Playwright — N/A (no WebUI product screen change)
• Build gates — system standalone clean install (no skipTests)
• Cross-platform — N/A (no path/file I/O)

Gates evidence

• modules_built: system
• build_evidence: cd system && ../mvnw.cmd clean install → BUILD SUCCESS; Tests run: 2073, Failures: 0, Errors: 0, Skipped: 241
• focused tests: 22 green (PSAssemblyBindingMapsTest 4, PSBinaryAssemblerSupportTest 3, PSNavHelperTypedTest 3, PSAssemblerUtilsTypedTest 4, PSServicesPackageTypedTest 8)
• downstream_checked: none — no public type made final/sealed; no public/protected method or ctor signature change. Added new helper types only.
• C5 UI: N/A (backend tech-debt only)

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

[natechadwick-intsof]

qa_deferred_quality — human QA not assigned.

This-run PR #3284 (parent #3280) is not a human-QA candidate and does not meet the overnight quality bar.

Candidate

• Not A — backend -Xlint / generics only (system assembly/jexl maps). No WebUI, Explorer, or user-visible flow.
• Not B — no installer / packaging / upgrade / host-visible behavior.
• Not C — no written acceptance that requires manual UAT after agent Maven proof.

Quality bar (live GitHub)

Gate	Result
Q1 PR open, not draft, MERGEABLE	pass (mergeable=MERGEABLE; mergeStateStatus=BLOCKED for reviews)
Q2 independent review APPROVE	fail — reviews=[], reviewDecision=REVIEW_REQUIRED. Kilo check success is not an APPROVE review.
Q3 required checks snapshot	pass — CodeQL / Analyze (java-kotlin) / Kilo Code Review SUCCESS; no pending/failing
Q4 C1 Maven evidence	pass — cd system && ../mvnw.cmd clean install BUILD SUCCESS in PR body
Q5 C5 UI proof	fail-if-treated-as-UI — no C5 surface commands (correct: not a UI PR)
Q6 slice	pass for the Xlint leftover
Q7 no overlapping open QA	pass
Q8 cycle verify	pass (status=passed; this PR was the integration tip)

Do not assign @vijaya-boddipudi. Tech-debt typing does not warrant a qa task.

Co-Authored by Grok Build using grok-4.5 with agent human-qa-handoff.