refactor: collapse v1/v2 constraint rendering onto TypedConstraint

[saishreeeee]

Description

• Route v1 persist_constraints through the Python TypedConstraint renderer instead of the Jinja constraint macros.
• Parse legacy meta.constraints in Python so v1 and v2 apply the same contract and Databricks constraint formats.
• Keep v1 behavior: skip unsupported constraints, generate stable names for unnamed ones, and still apply constraints on Hive Metastore.

Testing

• Unit tests for parse/render and constraint macros
• Functional persist_constraints on UC SQL warehouse
• Functional contract/constraint tests on UC SQL warehouse

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
dbt/adapters/databricks
constraints.py					135, 237, 316-317, 326-341
impl.py					1087-1088
dbt/adapters/databricks/relation_configs
constraints.py
Project Total

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