Rewrite UBS to use precomputed deltas and add deterministic demos

[Nullkernel]

Motivation

• Improve the Uniform Binary Search (UBS) probe logic to maintain valid probe intervals deterministically using precomputed deltas and a clear center-start flow.
• Provide a deterministic demonstration that shows both a found and a not-found search to make behavior explicit for users.

Description

• Rewrote binunisearch in Searching-algorithms/Uniform_binarysearch.java to build a delta table with buildDeltaTable(int n), start at a center probe, and move left/right by successive deltas while clamping the probe to [0, n-1].
• Kept exact-match semantics so the function returns an index only when arr[probe] == key and otherwise returns -1.
• Added buildDeltaTable to precompute the successive delta moves and runDeterministicDemo which runs two deterministic searches (one found, one not-found) and is invoked from main on key flow and some early-exit paths.
• Updated main to call the deterministic demo in invalid/early-exit cases and after a normal interactive run to demonstrate behavior.

Testing

• Compiled the updated file with javac Searching-algorithms/Uniform_binarysearch.java, which completed successfully.
• No automated unit tests were added; behavior was validated via the deterministic demo runs included in main.

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Codex Task