CBG-5260: remove panic call in rev cache Put

[gregns1]

CBG-5260

Removes explicit panic call in Put on revision cache. Adds validation on document revision and if invalid pass error up the stack for Put and Upsert methods.

Pre-review checklist

• Removed debug logging (fmt.Print, log.Print, ...)
• Logging sensitive data? Make sure it's tagged (e.g. base.UD(docID), base.MD(dbName))
• Updated relevant information in the API specifications (such as endpoint descriptions, schemas, ...) in docs/api

Dependencies (if applicable)

• Link upstream PRs
• Update Go module dependencies when merged

Integration Tests

• https://jenkins.sgwdev.com/job/SyncGatewayIntegration/588/

[Copilot]

Pull request overview

This PR removes the panic in the revision cache Put path by introducing structural validation for DocumentRevision and propagating errors from Put/Upsert up through the revision cache layers. It also updates callers/tests to handle the new error-returning signatures and adjusts memory-accounting tests to reflect history bytes being counted.

Changes:

• Change RevisionCache/collection wrappers/orchestrator/sharded cache Put and Upsert to return error, and update call sites to handle it.
• Add DocumentRevision.IsValid() validation and return a redactable error instead of panicking when required fields are missing.
• Update revision/delta cache tests to use valid history/body inputs and to assert the revised memory byte accounting; add a new test for invalid revision validation.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
rest/replicatortest/replicator_test.go	Updates test to assert Upsert returns no error after signature change.
db/revision_cache_test.go	Updates tests for new Put/Upsert error returns and revised memory accounting; adds invalid-revision test.
db/revision_cache_orchestrator.go	Propagates Put/Upsert errors and only triggers eviction on success.
db/revision_cache_lru.go	Removes panic, adds IsValid and returns validation errors from Put/Upsert.
db/revision_cache_interface.go	Updates RevisionCache interface and collection wrapper methods to return errors.
db/revision_cache_bypass.go	Updates bypass implementation to match new interface (returns nil error).
db/delta_cache_test.go	Adjusts delta cache test inputs/expectations to satisfy new validation and byte accounting.
db/crud.go	Handles revision cache insertion errors by logging (without failing the write).

[bbrks]

Looks mostly OK - think we should have better error reporting if docs end up in this invalid state