feat: implement milestone 2 write operations

[h3n4l]

Summary

Implement all 10 MongoDB write operations for Milestone 2:

Insert:

• insertOne(document, options)
• insertMany(documents, options)

Update:

• updateOne(filter, update, options)
• updateMany(filter, update, options)
• replaceOne(filter, replacement, options)

Delete:

• deleteOne(filter, options)
• deleteMany(filter, options)

Atomic find-and-modify:

• findOneAndUpdate(filter, update, options)
• findOneAndReplace(filter, replacement, options)
• findOneAndDelete(filter, options)

Supported options:

Option	Applies To
writeConcern	All write ops
bypassDocumentValidation	Insert, Update, Replace, FindOneAndUpdate/Replace
comment	All write ops
ordered	insertMany
upsert	Update, Replace, FindOneAndUpdate/Replace
hint	Update, Replace, Delete, FindOneAnd*
collation	Update, Replace, Delete, FindOneAnd*
arrayFilters	updateOne, updateMany, findOneAndUpdate
let	Update, Replace, Delete, FindOneAnd*
sort	updateOne, replaceOne, FindOneAnd*
projection	FindOneAnd*
returnDocument	FindOneAndUpdate/Replace

Note: wtimeout is parsed but ignored as it's not supported in MongoDB Go driver v2.

Test plan

• All existing tests pass
• Added integration tests for all 10 write operations in write_test.go
• Tests cover basic operations, upsert, returnDocument, sort options
• Lint passes with 0 issues

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Implements Milestone 2 MongoDB write operations by adding parsing + execution support for 10 write methods, along with integration tests and updated documentation.

Changes:

• Add translator support for insert/update/replace/delete/findOneAnd* write operations and their supported options.
• Add executor implementations for all 10 write operations using the MongoDB Go driver v2.
• Add integration tests for write operations and update docs/registry to reflect M2 is now supported.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
write_test.go	Adds integration tests covering the 10 new write operations.
internal/translator/visitor.go	Routes parsed method calls to new write-operation extractors and op types.
internal/translator/types.go	Introduces new OpTypes and Operation fields for write operations/options.
internal/translator/method_registry.go	Removes M2 write methods from “planned” registry now that they’re implemented.
internal/translator/collection.go	Implements argument/option extraction for all Milestone 2 write methods.
internal/executor/write.go	Implements execution logic for the 10 write operations and response formatting.
internal/executor/executor.go	Wires new write operation types into the executor dispatch.
error_test.go	Updates planned-operation test expectations now that insertOne is implemented.
README.md	Updates Milestone 2 documentation from “planned” to “supported” and lists options.

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[Copilot]

returnDocument is accepted for all findOneAnd* methods here, but it is documented as only applying to findOneAndUpdate/Replace (and the executor ignores op.ReturnDocument for findOneAndDelete). This results in silently ignoring a user-supplied option for findOneAndDelete. Consider rejecting returnDocument (UnsupportedOptionError) when methodName == "findOneAndDelete" to match the documented API surface and avoid surprising behavior.