TIME Type Precision Support in Foreign Key Constraints

Two tests in the time with foreign keys script are failing because our current implementation doesn't properly support TIME precision in foreign key constraints (dolthub/dolt#9544)

All TIME types in the codebase are normalized to TIME(6) internally, as confirmed in `/workspace/go-mysql-server/sql/types/time.go`. This can't distinguish between TIME(0) and TIME(6) at runtime, causing inconsistent behavior with foreign key constraints.

MySQL Behavior
```sql
-- Parent tables
CREATE TABLE parent_t0 (t TIME PRIMARY KEY);
CREATE TABLE parent_t6 (t TIME(6) PRIMARY KEY);
INSERT INTO parent_t0 VALUES ('12:34:56'); -- Stored as '12:34:56'
INSERT INTO parent_t6 VALUES ('12:34:56'); -- Stored as '12:34:56.000000'

-- Child tables with foreign keys
CREATE TABLE child_t0_p6 (t TIME, FOREIGN KEY (t) REFERENCES parent_t6(t));
CREATE TABLE child_t6_p0 (t TIME(6), FOREIGN KEY (t) REFERENCES parent_t0(t));

-- These inserts fail with foreign key violations
INSERT INTO child_t0_p6 VALUES ('12:34:56'); -- TIME(0) → TIME(6) - Fails
INSERT INTO child_t6_p0 VALUES ('12:34:56'); -- TIME(6) → TIME(0) - Fails
```

Start by reading /workspace/go-mysql-server/sql/types/time.go and running the two failing tests in the time with foreign keys script. Trace how TIME precision is represented during foreign-key checks; done means the TIME(0)/TIME(6) cases match the documented MySQL behavior without breaking existing foreign-key tests.

Written by the indexing model from the issue text.