Add tiling CLI flags and validation to sharp predict

[disk02]

Motivation

• Provide CLI surface and configuration plumbing for future tiled inference support so tiling options can be specified and passed through the predict flow.
• Enforce correct flag combinations and numeric ranges early to fail fast on invalid CLI usage.

Description

• Add new CLI options to predict_cli in src/sharp/cli/predict.py: --tiling, --tile-size (default 1536), --tile-overlap (default 0.25), and --tile-keep (default None) with help text.
• Parse and expose the new values via the predict_cli function signature so they are available to downstream code in later phases.
• Add early validation after argument parsing that --tiling requires --sbs-image and --fast-preview-render, that --tile-overlap is in [0.0, 0.5), and that --tile-keep (if provided) is in (0.0, 1.0] with clear click.ClickException errors.
• Keep changes localized to src/sharp/cli/predict.py and do not implement any tiling/runtime logic yet (values are stored for later phases).

Testing

• No automated tests were run for this phase (CLI plumbing only).

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Codex Task