Feature sqlbuilder

[KARTIKrocks]

Added

• sqlbuilder — New sqlbuilder package: fluent, type-safe SQL query builder with multi-dialect support (PostgreSQL, MySQL, SQLite)
• sqlbuilder — Select, Insert, Update, Delete builders with chainable API and Build() (string, []any) terminal method
• sqlbuilder — Dialect support: Postgres (default, $1, $2, ...), MySQL and SQLite (? placeholders) via SetDialect(d) or SelectWith(d, ...) / InsertWith(d, ...) / UpdateWith(d, ...) / DeleteWith(d, ...) constructors
• sqlbuilder — SELECT: Distinct, Column, Columns, ColumnExpr, From, FromAlias, FromSubquery
• sqlbuilder — JOIN support: Join, LeftJoin, RightJoin, FullJoin, CrossJoin with parameterized ON clauses
• sqlbuilder — WHERE conditions: Where, WhereEq, WhereNeq, WhereGt, WhereGte, WhereLt, WhereLte, WhereLike, WhereILike, WhereIn, WhereNotIn, WhereBetween, WhereNull, WhereNotNull, WhereExists, WhereNotExists, WhereOr, WhereInSubquery, WhereNotInSubquery — available on Select, Update, and Delete builders
• sqlbuilder — Automatic placeholder rebasing: each Where call uses $1-relative numbering, globally rebased at Build() time
• sqlbuilder — GroupBy, Having, OrderBy, OrderByAsc, OrderByDesc, OrderByExpr, Limit, Offset
• sqlbuilder — Row-level locking: ForUpdate, ForShare, SkipLocked, NoWait
• sqlbuilder — Set operations: Union, UnionAll, Intersect, Except
• sqlbuilder — CTEs: With, WithRecursive, WithSelect, WithRecursiveSelect on all builders
• sqlbuilder — INSERT: Columns, Values, ValueMap, BatchValues, FromSelect
• sqlbuilder — Upsert: OnConflictDoNothing, OnConflictUpdate, OnConflictUpdateExpr
• sqlbuilder — UPDATE: Set, SetExpr, SetMap, Increment, Decrement, multi-table From
• sqlbuilder — DELETE: Using for multi-table deletes
• sqlbuilder — Returning clause on Insert, Update, and Delete builders
• sqlbuilder — Expression helpers: Raw, RawExpr, Count, CountDistinct, Sum, Avg, Min, Max, Expr.As(alias)
• sqlbuilder — Request integration: ApplyPagination, ApplySort, ApplyFilters bridge request package types to query conditions
• sqlbuilder — When(cond, fn) conditional builder and Clone() deep copy on all builders
• sqlbuilder — All builders expose Build(), MustBuild(), Query(), and String() terminal methods