bug: active_workers counter never updated in summarization_worker.rs

[AlexMikhalev]

Issue Description

The active_workers counter in SummarizationWorker is checked but never updated, making it useless for controlling concurrency.

Location

crates/terraphim_service/src/summarization_worker.rs:252

Current Code

```rust
if !self.is_paused
&& self.active_workers < self.config.max_concurrent_workers
&& task_sender.try_send(task.clone()).is_ok()
```

The active_workers field is checked but never incremented/decremented anywhere in the code.

Impact

• MEDIUM priority - Logic bug
• The counter provides no actual concurrency control
• May lead to confusion about actual worker limits

Recommended Fix

Either:

1. Update the counter when tasks are started/completed
2. Remove the field entirely if not used

References

• Identified in code review for PR fix(zipsign): update zipsign API to v0.2 #429
• Related to summarization worker task management

[AlexMikhalev]

Phase 4 Verification Report

Status: BUG CONFIRMED - NOT FIXED

Evidence

In crates/terraphim_service/src/summarization_worker.rs:

• Line 100: active_workers: usize declared
• Line 113: Initialized to 0
• Line 251: Used in condition check
• NO INCREMENT/DECREMENT OPERATIONS anywhere in the file

Impact

The condition at line 250-252:

if !self.is_paused
    && self.active_workers < self.config.max_concurrent_workers

Since active_workers is always 0, the concurrency limit check is effectively bypassed.

Suggested Fix Options

1. Implement counter: Add increment before task processing, decrement after (requires Arc)
2. Remove dead code: If channel backpressure is sufficient, remove the unused field

Issue remains OPEN - needs implementation fix.

[AlexMikhalev]

Phase 1-2 Complete: Research and Design

Verification Status: STILL_OPEN (confirmed bug)

The active_workers counter is:

• Declared at line 100
• Initialized to 0 at line 113
• Checked at line 251: self.active_workers < self.config.max_concurrent_workers
• Never incremented or decremented

Recommended Fix: Remove Field, Use Processing Count

Channel backpressure already provides correct concurrency control via bounded mpsc::channel. The active_workers < max_concurrent_workers check is always true (0 < N) - effectively dead code.

Changes Required (single file):

1. Remove active_workers: usize from struct (line 100)
2. Remove active_workers: 0 from init (line 113)
3. Simplify submit_task check (lines 249-256)
4. Use processing_tasks count for stats (line 340)

Documents Created

• .docs/research-issue-432-active-workers.md
• .docs/design-issue-432-active-workers.md

Ready for Phase 3 (Implementation) upon approval.