Build/Test Tools: Remove the orphaned .eslintrc-jsdoc.js and rename lint:jsdoc

[mukeshpanchal27]

Problem

npm run lint:jsdoc does not lint JSDoc.

"lint:jsdoc": "wp-scripts lint-js",
"lint:jsdoc:fix": "wp-scripts lint-js --fix",

There is a .eslintrc-jsdoc.js at the repo root containing the intended rules, but:

• A repo-wide grep for eslintrc-jsdoc (excluding node_modules and package-lock.json)
  returns zero matches. The file is referenced nowhere.
• .eslintrc-jsdoc.js is not a filename ESLint resolves automatically, and the scripts pass
  no -c flag.

So wp-scripts lint-js falls back to the @wordpress/scripts default config and the JSDoc
rules never load. Nothing catches this, because neither script runs in CI — JS coding
standards runs npm run grunt jshint instead.

Why wiring it up is not the fix

package-lock.json resolves eslint to 10.7.0. The config file is dead in two
independent ways:

• ESLint 10 dropped legacy .eslintrc support. Confirmed structurally: eslint 10.7.0
  declares no @eslint/eslintrc dependency, and no package matching eslintrc appears
  anywhere in the lock tree. That package provides legacy config loading.
• valid-jsdoc and require-jsdoc — the only two rules the file configures — were
  deprecated in ESLint 5.10 and removed in ESLint 9.

Passing -c .eslintrc-jsdoc.js would hard-fail on an unreadable config referencing rules
that no longer exist.

Change

• Deletes the orphaned .eslintrc-jsdoc.js.
• Renames lint:jsdoc / lint:jsdoc:fix to lint:js / lint:js:fix, which is what they
  actually do.

Follow-up (not in this PR)

.eslintignore is also legacy eslintrc-era configuration that ESLint 10 no longer reads —
ignores now live in flat config.

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Draft proposal from a review of composer.json / package.json. Opened as a draft for discussion — not intended to merge as-is.