feat: convention-aligned dependency addition in PomEditor

[gnodet]

Summary

Add convention auto-detection to PomEditor.Dependencies so that when adding a dependency, the edit follows the project's existing dependency management style.

Claude Code on behalf of Guillaume Nodet

Motivation

Multiple tools need this capability:

• Pilot — interactive TUI promoting transitive deps to declared
• maven-dependency-plugin#1599 — dependency:add goal with -Dalign flag

Currently each consumer must implement its own convention detection. This logic belongs in domtrip-maven's PomEditor since it's a POM editing concern.

Proposed API

// High-level: detect conventions and add accordingly
editor.dependencies().addAligned(Coordinates coords);

// Or with explicit control:
editor.dependencies().addAligned(Coordinates coords, AlignOptions options);

Convention Detection

When adding a dependency, analyze existing <dependencies> and <properties> to detect:

1. Managed dependency style

• If most existing <dependency> entries are version-less (version delegated to <dependencyManagement>), the new dependency should be added the same way:
  • Add versioned entry to <dependencyManagement>
  • Add version-less <dependency>
• If most entries have inline versions, add with inline version

2. Version property style

• If most existing versions use ${...} property references, automatically create a version property
• If most use literal versions, use literal

3. Property naming convention

Detect the dominant pattern from existing properties:

• Dot suffix: guava.version → ${guava.version}
• Dash suffix: guava-version → ${guava-version}
• CamelCase: guavaVersion → ${guavaVersion}
• Dot prefix: version.guava → ${version.guava}

Apply the same pattern when creating new version properties.

Implementation Notes

• The PomEditor.Properties API already exists (updateProperty(), deleteProperty()) but is underutilized
• PomEditor.Dependencies already has updateDependency() and updateManagedDependency() — the aligned version composes these
• Explicit flags should always override detected conventions (e.g., force managed, force property, explicit property name)
• Detection should be based on majority vote — if 7/10 deps use properties, follow that pattern

Acceptance Criteria

• Detect managed vs inline version style
• Detect property vs literal version style
• Detect property naming convention
• addAligned() method that applies detected conventions
• Explicit overrides for all detected conventions
• Unit tests covering each convention pattern and mixed scenarios