Motivation

Follow-up to #3879 (vector.neighbors options map) and #3880 (fulltext.* options map). The four SQL graph path-finding functions have inconsistent option handling:

• shortestPath(src, dest [, direction [, edgeType [, {maxDepth, edge}]]]) - mixed positional + map, map only covers two knobs.
• dijkstra(src, dest, weight [, direction]) - single positional, primed for growth (edgeTypeNames, maxDepth, etc.).
• bellmanFord(src, dest, weight [, direction]) - same as dijkstra, plus a foreseeable detectNegativeCycles flag.
• astar(src, dest, weight [, {options}]) - already fully map-driven, but uses hand-rolled parsing that silently ignores unknown keys.

Proposal

• Route all four through com.arcadedb.function.sql.FunctionOptions so unknown keys throw a descriptive error and type coercion is consistent with vector.neighbors and fulltext.*.
• Let shortestPath, dijkstra, bellmanFord accept an options map that consolidates direction, edgeTypeNames, maxDepth, emptyIfMaxDepth, and (for shortestPath) edge. Existing positional forms stay for backward compatibility.
• astar keeps the same surface but swaps its bespoke parser for FunctionOptions, keeping the same accepted keys (direction, edgeTypeNames, vertexAxisNames, parallel, maxDepth, emptyIfMaxDepth, tieBreaker, dFactor, heuristicFormula, customHeuristicFormula).

Non-goals

• No grammar changes.
• No renames: these functions already use camelCase under the convention.

Deliverables

• Code: refactor the four functions through FunctionOptions.
• Tests: options-map form + unknown-key rejection.
• Docs: show options-map syntax alongside positional for each function.