Add a LeetCode Java solution

Turn an LC number (plus, usually, a draft sitting in ws/Workspace26.java) into a committed-quality Java file and the [Java] link on its README row, in the shape the other ~1626 files under leetcode_java/ already use.

Invocation: /lc-java <LC number> <Package> — e.g. /lc-java 25 LinkedList. A draft pasted under the command is used as the solution; with no draft, it is usually already in the workspace scratch file (step 2).

Missing arguments are inferred, not asked about: the package from the technique the solution actually uses, the class name from the problem title. Ask only if the number itself is missing or the package is genuinely ambiguous.

Wrong skill? This one owns leetcode_java/ only. A Python solution goes to /lc-python. The two are counterparts and share one README row — see directive 4.