fix: add view privilege (GRANT/REVOKE) support to plan/apply

[dilame]

Fixes #271

Summary

pg-schema-diff plan ignores VIEW ACL diffs — both missing GRANT and missing REVOKE. Table privileges work correctly, but views are completely excluded from the privilege pipeline.

Root cause

Three layers:

1. SQL query (internal/queries/queries.sql): GetTablePrivileges filters relkind IN ('r', 'p'), excluding views ('v')
2. Schema model (internal/schema/schema.go): View struct has no Privileges field
3. Diff/plan logic (pkg/diff/view_sql_generator.go): viewDiff has no privilegesDiff, Add() emits no GRANTs, Alter() does not diff privileges

Changes

• Include views (relkind = 'v') in GetTablePrivileges query
• Add Privileges []TablePrivilege to View struct (reuses existing type)
• Populate view privileges in fetchViews() via fetchPrivileges()
• Normalize view privileges in normalizeView()
• Wire privilege diffing into buildViewDiff() and viewSQLGenerator.{Add,Alter}
• Add 8 acceptance test cases covering: no-op, grant, revoke, multiple privileges, WITH GRANT OPTION, non-public schema, new view with privileges, drop view with privileges

Test plan

• All existing acceptance tests pass (no regressions)
• New TestViewPrivilegeCases covers grant, revoke, grant option, schema-qualified views
• Verify plan output includes GRANT/REVOKE for views

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