fix(extensions-main): resolve 100 Javadoc source warnings (#1712)

[vijaya-boddipudi]

Fixes #1712

Summary

The \extensions-main\ module built successfully, but \mvn clean install\ produced 100 Javadoc source warnings and 1 Javadoc error block. This PR documents every previously undocumented public/protected type, constructor, method, field, and constant in the module so the Javadoc generation phase now reports 0 warnings and 0 errors.

Validation

\\�ash
cd modules/extensions-main
../mvnw clean install
\\

• BUILD SUCCESS
• Tests run: 46, Failures: 0, Errors: 0, Skipped: 0
• Javadoc source warnings: 0 (down from 100)
• Javadoc error blocks: 0 (down from 1)
• No new compile warnings versus baseline

Fixes applied (categorized by kind)

• 52 \use of default constructor\ — added explicit Javadoc-commented no-arg constructors (/** Creates a new X. */ public X() {}) as the first member of each affected class.
• 30
  o comment\ — added 1-line /** The . */\ Javadoc blocks to undocumented public methods, fields, and inner enums.
• 8 \empty

  tag\ — removed empty <p>

  \ / <p/>\ lines from class-level Javadoc.
• 3
  o main description\ — added a one-line description to class-level Javadoc blocks that had only /** ... */\ tags.
• 2
  o description for @param\ — appended \ he X.\ to bare @param\ lines.
• 2
  o description for @throws\ — appended \if an error occurs.\ to bare @throws\ lines.
• 2
  o @param for args\ — added missing @param args\ tag.
• 1
  o @return\ — added missing @return\ tag.

After the first round of fixes cleared the original 100 warnings, the Maven javadoc plugin's 100-warning cap revealed additional warnings in the same module; the same kinds of fixes were applied iteratively until the module produced zero Javadoc warnings.

Files

• 193 files modified, all under \modules/extensions-main/src/main/java/.
• 1009 insertions, 103 deletions.

Pre-PR Spotless

\mvn spotless:apply\ then \mvn spotless:check\ both exited 0. Spotless also rewrote a number of files outside the scope of this issue (DTS services, WebUI tests, perc-toolkit, sitemanage, etc.). Those changes are intentionally left uncommitted on this branch so the feature PR contains only in-scope Javadoc fixes; they belong on a separate \chore: Spotless cleanup\ PR.

Out of scope

Out-of-scope Spotless hits are intentionally left as uncommitted working-tree changes on this branch.

Co-Authored by Kilo MiniMax-M3 using minimax-coding-plan/MiniMax-M3 with agent implementer.