fix(image-routing): detect Windows image paths

[kohoj]

Problem

extract_image_refs() only recognized POSIX-style / and ~/ image paths. On native Windows, kanban task-body image enrichment silently skipped drive-letter paths such as C:\Users\Hiro\shot.png. Fixes #61568.

Root cause

agent/image_routing.py claimed to match the gateway extract_local_files() shape, but its local-image regex was never updated after #34632 added Windows drive-letter support to the gateway path. It also deduped before path normalization.

Fix

• Extend the local-image regex to accept absolute Windows drive-letter paths with / or \ separators.
• Normalize expanded local paths before file checks and dedupe with normcase() so native Windows separator/case normalization is respected.
• Set USERPROFILE in the tilde expansion test so the same test matches Python's Windows expanduser() behavior.
• Add platform-independent regression tests for Windows drive-letter paths, lowercase drives, relative-drive non-matches, and URL lookbehind behavior.

Tests

• scripts/run_tests.sh tests/agent/test_image_routing.py -q
• scripts/run_tests.sh tests/hermes_cli/test_kanban_worker_image_extraction.py -q

Repro

On current main, _LOCAL_IMAGE_PATH_RE returns no match for C:\Users\Hiro\shot.png, C:/Users/Hiro/shot.png, or c:/shot.PNG. After the fix, all three match and still pass the existing file-existence gate.

[alt-glitch]

This was generated by AI during triage.

Duplicate of #34374 (earliest open PR) — both extend agent/image_routing.py's _LOCAL_IMAGE_PATH_RE with the same [A-Za-z]:[/\\] Windows drive-letter alternation. This PR additionally adds normcase() deduping (a minor extra), but the core fix is the same. Related to the bug spec #61568.

[teknium1]

Thanks for the focused Windows fix. The premise is confirmed on current main: agent/image_routing.py:69 accepts only ~/ and /, while the kanban worker calls extract_image_refs() on the task body at cli.py:16073. The proposed drive-letter and mixed-separator pattern matches the established gateway implementation at gateway/platforms/base.py:3730 (commit 51d165a8e).

The PR’s regression cases cover backslash and slash drive paths, lowercase drives, relative-drive rejection, and URL lookbehind. The implementation is narrow and does not alter tool schemas, session state, or prompt caching.

Automated hermes-sweeper review.