Refactor logger alias to optic and remove dead code

[sanatmehrotra]

Purpose / Description

Two small housekeeping fixes in the server middleware layer:

1. audit.py — The Loguru import used the bare logger name instead of the
   project-wide optic alias mandated by AGENTS.md. All 40+ other files in the
   codebase already use from loguru import logger as optic; this was the last
   outlier, making grep/search across the codebase inconsistent.

2. main.py — A bare pass statement appeared immediately before an
   optic.warning(...) call in the same block. This implied the block was a
   silent no-op when it actually emits a warning, making the control flow
   misleading to readers. Removing pass restores clear intent.

Fixes

• No open issue — pure code-quality / consistency cleanup.

Approach

• audit.py: Changed from loguru import logger → from loguru import logger as optic
  and updated all call sites in the file from logger.* → optic.*. No behaviour change.

• main.py: Deleted the dead pass statement. The warning log and any
  subsequent logic in the block are unaffected.

How Has This Been Tested?

• Existing test suite (make test) passes without modification — no logic was
  changed, only naming and dead-code removal.
• Manually verified that optic.warning(...) still fires as expected by
  reading the surrounding control flow.
• make lint (ruff check) passes cleanly on both files.

Learning (optional)

• AGENTS.md § Optic (dev logging): "Import: from loguru import logger as optic" —
  the alias is intentional so log calls are grep-distinguishable from third-party
  libraries that also use logger.

Checklist

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (N/A — no UI changes)

[CLAassistant]

All committers have signed the CLA.