feat(event): add reactive runtime event plumbing

[omarluq]

Summary

• expose additional assistant lifecycle payloads on the runtime event stream
• publish context/usage events through the shared event naming path
• add coverage around lifecycle ordering updates

Validation

• mise exec -- task ci

Note: this is intended to stack after #23; GitButler would not attach the branch to the stack locally due to the current base segment state.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 9def230f-f9c2-49bd-af4e-f10f33e507df

📥 Commits

Reviewing files that changed from the base of the PR and between 191fc11 and e853469.

📒 Files selected for processing (5)

• internal/assistant/client.go
• internal/assistant/lifecycle.go
• internal/assistant/runtime.go
• internal/assistant/runtime_lifecycle_test.go
• internal/assistant/usage_events.go

✅ Files skipped from review due to trivial changes (1)

• internal/assistant/client.go

🚧 Files skipped from review as they are similar to previous changes (3)

• internal/assistant/runtime_lifecycle_test.go
• internal/assistant/usage_events.go
• internal/assistant/lifecycle.go

---

📝 Walkthrough

Summary by CodeRabbit

• New Features

  • Added a context-build lifecycle event exposing session context details such as message counts and token estimates.

• Improvements

  • Standardized the token-usage field name across lifecycle events.
  • Enhanced token estimation output to include per-role message counts and estimated token breakdowns.

• Tests

  • Updated tests to assert the new context-build lifecycle event in success and error flows.

Walkthrough

Adds a jsonUsageKey constant, updates usage emission and turn-end payload to use it, introduces a context_build lifecycle event with payload and helpers, calls the dispatch during model response handling, and updates tests to assert the new event.

Changes

Lifecycle Event and Usage Key Standardization

Layer / File(s)	Summary
Usage key constant and refactoring internal/assistant/client.go, internal/assistant/usage_events.go, internal/assistant/lifecycle.go	Introduce jsonUsageKey constant and replace hardcoded "usage" references in usage emission and the turn-end lifecycle payload.
Context-build lifecycle event dispatch and payload internal/assistant/lifecycle.go, internal/assistant/runtime.go	Add Runtime.dispatchContextBuild and contextBuildLifecyclePayload (message counts, token estimates, per-role counts, usage), and invoke dispatch from modelResponse.
Context-build event test coverage internal/assistant/runtime_lifecycle_test.go	Register context_build in the Lua lifecycle test extension and verify it appears in ordered event sequences for both success and error scenarios.

🎯 3 (Moderate) | ⏱️ ~20 minutes

• omarluq/librecode#23: Prior PR introducing session/turn lifecycle emission and turn-end payloads; this change builds on that lifecycle emission structure.

"A rabbit in the code did pry,
Added keys and watched events fly,
Tokens counted, contexts made,
Tests hop in to mark the parade. 🐇✨"

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: adding reactive runtime event plumbing to expose lifecycle payloads on the event stream.
Description check	✅ Passed	The description is directly related to the changeset, outlining the three main objectives of exposing lifecycle payloads, publishing events through shared paths, and adding test coverage.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/ro-runtime-events

---

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@internal/assistant/lifecycle.go`:
- Around line 129-139: The new dispatchContextBuild, and its helper
contextBuildLifecyclePayload, are never called (dead code), so wire
runtime.dispatchContextBuild(...) into the context construction/execution path
where the active prompt and messages are assembled (the same place that
currently builds systemPrompt, messages []database.MessageEntity, sessionID, cwd
and usage before executing the prompt). Locate the routine that prepares the
prompt context (e.g., the method that constructs or executes the prompt for
Runtime), and after assembling sessionID, cwd, systemPrompt, messages and usage,
call runtime.dispatchContextBuild(ctx, sessionID, cwd, systemPrompt, messages,
usage) so the context_build lifecycle event is emitted; ensure you pass the same
values used for prompt execution and keep the existing runtime.dispatchLifecycle
usage intact (it will reuse dispatchContextBuild’s payload via
contextBuildLifecyclePayload).

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: fa7fad34-5f54-4919-9ee7-fdbafe4500d8

📥 Commits

Reviewing files that changed from the base of the PR and between 44ebeb9 and 191fc11.

📒 Files selected for processing (4)

• internal/assistant/client.go
• internal/assistant/lifecycle.go
• internal/assistant/runtime_lifecycle_test.go
• internal/assistant/usage_events.go

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov-commenter]

Codecov Report

❌ Patch coverage is 96.29630% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 57.36%. Comparing base (44ebeb9) to head (e853469).

Files with missing lines	Patch %	Lines
internal/assistant/usage_events.go	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #28      +/-   ##
==========================================
+ Coverage   57.29%   57.36%   +0.06%     
==========================================
  Files         160      160              
  Lines       15758    15782      +24     
==========================================
+ Hits         9029     9053      +24     
  Misses       5767     5767              
  Partials      962      962              

Flag	Coverage Δ
unittests	57.36% <96.29%> (+0.06%)	⬆️

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