🤖 refactor: auto-cleanup (#2833)

## Summary

Periodic auto-cleanup of dead code discovered by scanning for unused
exports.

## Changes

1. **Remove unused `isBashTaskId` export**
(`src/node/services/tools/taskId.ts`)
- Deleted in previous cleanup cycle: `taskToolTypeGuards.ts` (PR #2833
initial commit)
- This cycle: removed `isBashTaskId` — a function defined but never
imported or called anywhere in the codebase (no production code, no
tests). It was a trivial wrapper around `fromBashTaskId` converting
`null` to `boolean`.

## Validation

- `make static-check` passes (ESLint, TypeScript, Prettier all green).
- Verified with exhaustive grep: no file in `src/` or `tests/`
references `isBashTaskId`.

Auto-cleanup checkpoint: db6b776

---

_Generated with `mux` • Model: `anthropic:claude-opus-4-6` • Thinking:
`xhigh` • Cost: `$unknown`_

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---------

Co-authored-by: mux-bot[bot] <264182336+mux-bot[bot]@users.noreply.github.com>

Author: mux-bot[bot]

src/common/utils/tools/taskToolTypeGuards.ts

@@ -18,7 +18,3 @@ export function fromBashTaskId(taskId: string): string | null {
   const processId = taskId.slice(BASH_TASK_ID_PREFIX.length).trim();
   return processId.length > 0 ? processId : null;
 }
-
-export function isBashTaskId(taskId: string): boolean {
-  return fromBashTaskId(taskId) !== null;
-}