Pipe structured BuilderProblems directly into DiagnosticCollector instead of re-logging as text

[gnodet]

Context

PR #12572 (Build Report Foundation) introduced a warning collection pipeline that intercepts SLF4J WARN-level log calls via BuildReportCollector.captureLogEvent() and auto-creates BuilderProblem objects with synthetic keys (auto:xxx).

However, Maven already creates structured BuilderProblem objects during model/settings/toolchains validation (with key, suggestion, documentationUrl, source:line:column). These are currently re-logged as plain text by DefaultProjectsSelector and DefaultMaven.buildGraph(), losing all structured metadata.

Problem

When the SLF4J hook intercepts the re-logged text, it creates a new synthetic BuilderProblem with:

• An auto-generated key (auto:logger-name:hash) instead of the original meaningful key
• No suggestion
• No documentationUrl
• No source location

The original structured BuilderProblem data is discarded.

Proposed Solution

Phase 1: Model validation problems

In DefaultProjectsSelector and DefaultMaven.buildGraph(), after logging model problems at WARN level, pipe the original BuilderProblem directly into DefaultDiagnosticCollector:

// Current code:
LOGGER.warn(problem.getMessage());

// Proposed:
LOGGER.warn(problem.getMessage());
diagnosticCollector.report(problem); // preserves key, suggestion, docUrl, source location

The SLF4J hook should then skip auto-creating a synthetic problem when a structured one was already reported for the same message (dedup by message hash).

Phase 2: Settings and toolchains validation

In LookupInvoker (line 746) and MavenInvoker (line 218), same pattern — pipe settings/toolchains BuilderProblem objects directly instead of only logging their message text.

Phase 3: Plugin Validation Manager

DefaultPluginValidationManager operates a completely separate warning collection pipeline with its own ConcurrentHashMap<String, PluginValidationIssues>. The session-end summary is logged at WARN (captured by SLF4J hook), but the individual plugin validation issues (deprecated mojos, Maven 2 deps, etc.) with their plugin GAV, locality, and mojo info are lost.

Create structured BuilderProblem objects for each plugin validation issue and report them to the DiagnosticCollector, enriched with:

• key: e.g. plugin-deprecated-mojo, plugin-maven2-dependency
• source: plugin GAV (groupId:artifactId:version)
• suggestion: e.g. "Update to Maven 4 API" or "Remove maven-compat dependency"
• documentationUrl: link to Maven plugin development guide

Validators affected

Validator	Current behavior	After fix
DefaultModelValidator (~35 sites)	BuilderProblem → re-logged as text → lost	Structured piping
DefaultSettingsValidator (~15 sites)	BuilderProblem → re-logged as text → lost	Structured piping
DefaultToolchainsBuilder	BuilderProblem → re-logged as text → lost	Structured piping
DeprecatedPluginValidator	Own collection → session-end summary text	Structured BuilderProblem
Maven2DependenciesValidator	Own collection → session-end summary text	Structured BuilderProblem
Maven3CompatDependenciesValidator	Own collection → session-end summary text	Structured BuilderProblem
MavenScopeDependenciesValidator	Own collection → session-end summary text	Structured BuilderProblem
ReadOnlyPluginParametersValidator	Own collection → session-end summary text	Structured BuilderProblem
Profile activators (File, JDK)	BuilderProblem → re-logged as text → lost	Structured piping

Expected Outcome

mvnlog and mvnlog --diagnostics display the full structured information:

Problems: 2 warnings

  [WARN]  'prerequisites' is deprecated   pom.xml
          key: deprecated-prerequisites
          suggestion: Use the maven-enforcer-plugin instead
          docs: https://maven.apache.org/pom.html#prerequisites

  [WARN]  Plugin uses deprecated Maven 2 API   maven-shade-plugin:3.5.0
          key: plugin-maven2-dependency
          suggestion: Update to a version that uses Maven 4 API

Depends on

• Build Report Foundation — structured report, console modes, warning control #12572 (Build Report Foundation)