refactor(weave): break up clickhouse_batched into components

[gtarpenning]

Description

strict refactor of our largest server file. it is becoming impossible for agents to easily edit, I suspect there is similar fatigue among humans too.

New structure:

clickhouse_query_layer/
├── trace_server.py           # Main orchestration layer, composes all repositories
├── client.py                 # ClickHouse connection, pooling, _query/_insert/_command
├── batching.py               # Async batch management for call start/end inserts
├── schema.py                 # Pydantic models for CH insertables (calls, objects, files, etc.)
├── settings.py               # Configuration constants (batch sizes, limits, table suffixes)
├── migrator.py               # Schema migrations for replicated/distributed modes
├── calls.py                  # CallsRepository: CRUD + streaming + stats
├── objects.py                # ObjectsRepository: CRUD + versioning
├── tables.py                 # TablesRepository: row CRUD + queries
├── files.py                  # FilesRepository: chunked file storage
├── feedback.py               # FeedbackRepository: annotations/reactions
├── refs.py                   # RefsRepository: reference resolution
├── costs.py                  # CostsRepository: token cost lookups
├── annotation_queues.py      # AnnotationQueuesRepository: queue management
├── threads.py                # ThreadsRepository: conversation threads
├── stats.py                  # StatsRepository: project/call statistics
├── otel.py                   # OtelRepository: OpenTelemetry span export
├── v2_api.py                 # V2ApiRepository: newer API endpoints
├── completions.py            # CompletionsRepository: LLM completion proxying
├── query_builders/           # SQL query builders for ClickHouse
│   ├── annotation_queues.py  # Queue item queries, pop/add operations
│   ├── objects.py            # Object metadata queries, val queries
│   ├── project.py            # Project stats queries
│   ├── tables.py             # Table row queries with pagination
│   ├── threads.py            # Thread listing queries (CH + SQLite variants)
│   └── calls/                # Complex call query building
│       ├── calls_query_builder.py      # Main CallsQuery class with filters/sorting
│       ├── call_metrics_query_builder.py # Aggregation metrics (avg, sum, etc.)
│       ├── usage_query_builder.py      # Usage stats with time bucketing
│       ├── object_ref_query_builder.py # Object reference joins and lookups
│       ├── optimization_builder.py     # Query optimization passes
│       ├── stats_query_base.py         # Shared base for stats queries
│       ├── cte.py                      # CTE (Common Table Expression) helpers
│       └── utils.py                    # SQL formatting utilities

Testing

Existing coverage

[wandbot-3000]

Preview this PR with FeatureBee: https://beta.wandb.ai/?betaVersion=44ce7296ec7ac26bfceff645efcc6379d1752e9d

[codecov]

Codecov Report

❌ Patch coverage is 84.02043% with 438 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...eave/trace_server/clickhouse_query_layer/v2_api.py	82.34%	55 Missing and 31 partials ⚠️
...trace_server/clickhouse_query_layer/completions.py	66.37%	59 Missing and 18 partials ⚠️
...se_query_layer/query_builders/annotation_queues.py	25.92%	59 Missing and 1 partial ⚠️
...eave/trace_server/clickhouse_query_layer/client.py	79.78%	25 Missing and 12 partials ⚠️
...ve/trace_server/clickhouse_query_layer/batching.py	82.14%	26 Missing and 4 partials ⚠️
weave/trace_server/clickhouse_query_layer/calls.py	93.71%	11 Missing and 15 partials ⚠️
...eave/trace_server/clickhouse_query_layer/tables.py	86.30%	9 Missing and 11 partials ⚠️
weave/trace_server/clickhouse_query_layer/otel.py	81.90%	12 Missing and 7 partials ⚠️
...ve/trace_server/clickhouse_query_layer/feedback.py	73.43%	17 Missing ⚠️
weave/trace_server/clickhouse_query_layer/files.py	82.82%	11 Missing and 6 partials ⚠️
... and 6 more

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