Fix Windows compatibility: /dev/tty fallback and process tree termination

[PowerSynth-max]

What does this PR do?
Fix two Windows-specific compatibility issues that affect Hermes stability and resource management on Windows platforms.

Related Issue
No existing issue found. This PR addresses real-world Windows compatibility problems discovered during local development and testing.

Type of Change
[x] 🐛 Bug fix (non-breaking change that fixes an issue)
Changes Made
cli.py (line ~1144): Added platform check in _reset_terminal_input_modes() to use CON device on Windows instead of /dev/tty
tools/environments/local.py (line ~660): Changed Windows branch in _kill_process() to use taskkill /T /F /PID for terminating the entire process tree, with fallback to proc.terminate()
How to Test
Test 1 (cli.py): Redirect stdout and verify no FileNotFoundError on Windows when exiting TUI
Test 2 (local.py): Create a process with child processes, call _kill_process(), verify all child processes are terminated (no orphan processes remain)
Test 3: Run existing test suite on Windows to ensure no regressions
Checklist
Code
[x] I've read the Contributing Guide
[x] My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
[x] I searched for existing PRs to make sure this isn't a duplicate
[x] My PR contains only changes related to this fix/feature (no unrelated commits)
[ ] I've run pytest tests/ -q and all tests pass (Note: Full test suite not run due to environment limitations)
[ ] I've added tests for my changes (Note: Manual testing performed, automated tests not added)
[x] I've tested on my platform: Windows 11
Documentation & Housekeeping
[x] I've updated relevant documentation — or N/A
[x] I've updated cli-config.yaml.example if I added/changed config keys — or N/A
[x] I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
[x] I've considered cross-platform impact (Windows, macOS) per the compatibility guide
[x] I've updated tool descriptions/schemas if I changed tool behavior — or N/A

Note: Some code was AI-assisted, reviewed and tested by human.

[alt-glitch]

This was generated by AI during triage.

Duplicate of #49460 (and competing with #54235): the tools/environments/local.py change here swaps the _IS_WINDOWS branch of _kill_process from proc.terminate() to taskkill /T /F /PID for whole-tree termination, which is byte-for-byte the same code site and mechanism as the earlier open #49460 (canonical) and #54235.

Note: this PR ALSO bundles a distinct, independently-useful fix in cli.py (_reset_terminal_input_modes_on_exit() opens CON instead of /dev/tty on Windows to avoid a FileNotFoundError on TUI exit) that the cluster PRs do not cover. A maintainer may want to salvage that cli.py hunk separately.

[PowerSynth-max]

Hi @alt-glitch, Thanks for the quick review and for identifying the overlap! You're absolutely right — the `local.py` change is indeed a duplicate of #49460 and #54235. I wasn't aware those PRs existed when I submitted this. However, as you noted, the `cli.py` fix (using `CON` instead of `/dev/tty` on Windows) is a distinct issue that those other PRs don't address. This was discovered during actual testing on Windows 11. **Questions for maintainers:** 1. Should I close this PR and submit a new one with only the `cli.py` changes? 2. Or would you prefer to keep this PR open and cherry-pick the `cli.py` hunk separately? 3. Or should I just remove the `local.py` changes from this PR and keep the `cli.py` fix here? Happy to follow whatever workflow makes the most sense. Thanks again for the review!

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