feat(table): make Table a resolved handle and the home of operator creation

[lucasfang]

Purpose

Linked issue: close #441

Table held only a schema, an identifier and a UUID: the resolution Catalog::GetTable() had just performed — which file system serves the table, where its root is — was discarded at the door. The four operator builds (about 1400 lines in four separate .cpp files) each re-derived the table's components from a context, Table::NewXxx were thin forwarders to the static Creates, and Table::Create read the schema through a SchemaManager it then threw away, so every operator re-read the same schema file through a manager of its own.

Changes:

• include/paimon/catalog/table.h: Table now carries the per-table file system, root path, schema, identifier, UUID, and schema/snapshot managers bound to that file system, root path and branch. New accessors GetFileSystem(), GetRootPath(), GetSchemaManager(), GetSnapshotManager(), CurrentBranch(); the constructor takes (file_system, root_path, schema, identifier, uuid, schema_manager). include/paimon/type_fwd.h gains the SchemaManager / SnapshotManager forward declarations.
• src/paimon/core/table/table.cpp plus the new internal header src/paimon/core/table/table_operators.h: the four operator builds move here verbatim behind CreateTableScan / CreateTableRead / CreateFileStoreWrite / CreateFileStoreCommit. The four operator .cpp files shrink to forwarders, and Table::NewScan/NewRead/NewWrite/NewCommit route through the same functions — one build path, with the table as the entry point. Table::Create reads the schema through the manager it hands to the table, so the open-time read warms the cache the table keeps.
• Catalogs populate the resolved state: FileSystemCatalog::GetTable opens a system table with the data table's root path; RestCatalog::GetTable reads the UUID, location and schema from one response (avoiding mixed generations after a table recreation) and opens the table with the per-table file system (LoadTableSchema gains a table_path out-parameter); MockVersionManagedCatalog serves the per-table file system the same way.
• examples/read_write_demo.cpp opens the table via catalog->GetTable and creates all four operators through table->NewXxx(...).

The moved operator bodies are unchanged (pure relocation): the operators still build their components from the context — wiring them to the table-held managers is a follow-up.

Tests

• New TableTest cases: TestCreateHoldsTheFileSystem (fs + root path retained), TestManagersBoundToTheTable (managers bound to the table's fs/path/branch; the kept schema manager serves the schema Table::Create read, i.e. the warmed cache; a branch table keeps branch-bound managers), TestCurrentBranch (main default, identifier-named branch), TestCatalogOpenedTableServesThePerTableFileSystem (no fs handed out → no managers; per-table fs served when issued), TestCreateBuildsTheOperator (the four Xxx::Create build through a catalog-configured context). FileSystemCatalogTest.TestOptionsSystemTableCatalog and TestCreateTableWithBlob assert the root path a table carries (a system table gets the data table's path).
• Actual runs: cmake --build build --target paimon-core-test -j 96 built clean; ./build/release/paimon-core-test --gtest_filter='TableTest.*:FileSystemCatalogTest.*' passed 45/45; the full suite ctest -j 96 in build/ (Release) passed 31/31 targets; git diff main HEAD --check clean.
• RestCatalog::GetTable is not compiled locally: both local build directories have PAIMON_ENABLE_REST=OFF, so REST coverage relies on CI.

API and Format

Yes, a breaking C++ API change in include/paimon/catalog/table.h: the public Table constructor changes from (schema, identifier, uuid) to (file_system, root_path, schema, identifier, uuid = "", schema_manager = nullptr), so direct constructions must be updated (all in-tree ones are). New read-only accessors are added; the signatures and behavior of the four Xxx::Create(context) statics and of Table::NewXxx(context) are unchanged. No storage format or protocol change.

Documentation

No new user-facing option or feature; the resolved-handle semantics and the manager lifetimes are documented in the Table class doc comments.

Generative AI tooling

Generated-by: Qoder

[lxy-9602]

+1