refactor(adk): consolidate store implementations

[cofin]

What changed

• share common configuration, table state, logging, and lifecycle helpers across synchronous and asynchronous ADK base stores
• implement synchronous adapter operations directly instead of forwarding through duplicate private wrappers
• hoist adapter DDL templates so synchronous and asynchronous stores consume the same SQL definitions
• centralize memory-store and artifact-backend sync/async dispatch
• centralize owner-column configuration handling
• align Oracle sync hash-partition DDL with the session table primary key used by the async store

Why

ADK session, memory, and artifact implementations had parallel paths that were costly to keep aligned. Consolidating their shared state, SQL, and dispatch behavior reduces drift while retaining each adapter's native database operations.

Impact

No public API changes are intended. Existing synchronous and asynchronous stores retain their contracts, and adapter-specific SQL remains adapter-owned. Oracle sync session tables configured for hash partitioning now partition on the existing id column instead of the nonexistent session_id column. Spanner and BigQuery implementations are unchanged.

Validation

• complete ADK extension unit suite
• concrete session, memory, and artifact store slot/property contracts
• sync/async DDL equivalence across Psycopg, CockroachDB, MySQL Connector, and every Oracle JSON storage mode
• owner-column, generated-column, covering-index, locality, table-option, and Oracle partition interpolation branches
• focused Psycopg, CockroachDB, MySQL Connector, and Oracle unit suites
• complete 17-backend ADK integration contract matrix
• make lint
• make type-check

[codecov-commenter]

Codecov Report

❌ Patch coverage is 86.45161% with 63 lines in your changes missing coverage. Please review.
✅ Project coverage is 76.92%. Comparing base (6bb5742) to head (e743f10).

Files with missing lines	Patch %	Lines
sqlspec/adapters/psycopg/adk/store.py	80.61%	17 Missing and 2 partials ⚠️
sqlspec/extensions/adk/store.py	79.22%	16 Missing ⚠️
sqlspec/adapters/cockroach_psycopg/adk/store.py	92.45%	7 Missing and 1 partial ⚠️
sqlspec/adapters/mysqlconnector/adk/store.py	88.70%	5 Missing and 2 partials ⚠️
sqlspec/adapters/sqlite/adk/store.py	91.30%	5 Missing and 1 partial ⚠️
sqlspec/extensions/adk/memory/service.py	73.33%	4 Missing ⚠️
sqlspec/extensions/adk/artifact/service.py	62.50%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #638      +/-   ##
==========================================
+ Coverage   76.82%   76.92%   +0.10%     
==========================================
  Files         473      473              
  Lines       66108    65850     -258     
  Branches     9821     9793      -28     
==========================================
- Hits        50785    50656     -129     
+ Misses      12031    11907     -124     
+ Partials     3292     3287       -5     

Flag	Coverage Δ
integration	59.99% <68.81%> (-0.05%)	⬇️
py3.10	75.17% <86.45%> (+0.10%)	⬆️
py3.11	75.19% <86.45%> (+0.11%)	⬆️
py3.12	75.18% <86.45%> (+0.09%)	⬆️
py3.13	75.18% <86.45%> (+0.09%)	⬆️
py3.14	76.11% <86.45%> (+0.09%)	⬆️
unit	64.14% <76.98%> (+0.21%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
sqlspec/adapters/oracledb/adk/store.py	61.24% <ø> (+1.77%)	⬆️
sqlspec/extensions/adk/_config_utils.py	85.26% <100.00%> (+2.10%)	⬆️
sqlspec/extensions/adk/artifact/store.py	84.84% <100.00%> (+11.03%)	⬆️
sqlspec/extensions/adk/memory/store.py	85.13% <100.00%> (+7.35%)	⬆️
sqlspec/extensions/adk/artifact/service.py	29.91% <62.50%> (+4.49%)	⬆️
sqlspec/extensions/adk/memory/service.py	37.66% <73.33%> (+8.67%)	⬆️
sqlspec/adapters/sqlite/adk/store.py	77.57% <91.30%> (-1.10%)	⬇️
sqlspec/adapters/mysqlconnector/adk/store.py	64.42% <88.70%> (+1.06%)	⬆️
sqlspec/adapters/cockroach_psycopg/adk/store.py	63.89% <92.45%> (+1.01%)	⬆️
sqlspec/extensions/adk/store.py	71.52% <79.22%> (-2.25%)	⬇️
... and 1 more

... and 5 files with indirect coverage changes

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