rts: add to activity log

[marksvc]

• Adds more middleware hooks.
• Remove use of AgentInternal from realtime-server.ts. Add
  declarations to Agent as needed. This had fallout such as accounting
  for agent possibly being null by type when checking things like
  context.agent?.clientId.
• Changed some error messaging from saying the op, to just the op
  path. This information flows into the activity logs.
• Some Byte size measuring is now being done in realtime usage of the
  server, not just upon intermittent SIGUSR2 request.
• Clarified typing for agent.connectSession resulted in some null
  guards + throw being added.
• ResourceMonitor now cares if it's "enabled", because if so it will
  build up some information over time to flush out on request.
• ResourceMonitor logs some additional information to a new file,
  resource-usage.jsonl, alongside existing .csv files.
• The change to resource-monitor.ts subscribedDocsCount is a fix from
  incorrect behaviour.
• An AGENTS.md file was placed alongside our sharedb typings to give
  specific instructions to AI on how to treat these.
• sharedb typings received various enhancements. Including declaring
  our custom property, connectSession.

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Open in Devin Review

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This change is 

[marksvc]

Labeling as "do not merge" so I can be involved in the timing, and able to watch when the code starts to be used on the staging server. But I do want the PR to be reviewed :).

[codecov]

Codecov Report

❌ Patch coverage is 79.23497% with 38 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.97%. Comparing base (36cc0e2) to head (3e9d149).
⚠️ Report is 9 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/RealtimeServer/common/resource-monitor.ts	63.51%	23 Missing and 4 partials ⚠️
src/RealtimeServer/common/realtime-server.ts	89.41%	9 Missing ⚠️
...timeServer/common/services/project-data-service.ts	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4093      +/-   ##
==========================================
+ Coverage   80.94%   80.97%   +0.02%     
==========================================
  Files         664      664              
  Lines       42152    42308     +156     
  Branches     6916     6993      +77     
==========================================
+ Hits        34120    34258     +138     
  Misses       6882     6882              
- Partials     1150     1168      +18     

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[marksvc]

src/RealtimeServer/common/activity-logger.ts line 42 at r1 (raw file):

 * reports produced by ResourceMonitor. Logging is controlled by the SF_RTS_LOG_LEVEL environment variable.
 */
export class ActivityLogger {

Note: AI code review identifies various cracks in the design of the logging and resource usage reporting system. I've sought to make it work well, and defend against various situations, but it's less important that the reporting system work flawlessly and more important that we get more reporting.

[marksvc]

I marked this PR as testing not required. The testing I want to see (beyond what I've done) is the E2E test pass, and usage on QA by the test team.

[github-actions]

📸 Screenshot diff deployed! (1 change)

View the visual diff at: https://pr-4093--sf-screenshot-diffs.netlify.app

[marksvc]

The motivation for this PR is to add lots more information to the RealtimeServer activity log, to aid in understanding what is happening when we see the resource usage increasing.

[pmachapman]

@pmachapman reviewed 15 files and all commit messages, made 1 comment, and resolved 1 discussion.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on marksvc).