Parent: #14182
Depends on: #14587 (PR 2)

Goal

Move gateway/ into hermes_agent/gateway/. First PR with a large test diff (1,224 test import refs, ~178 test files). Production callers concentrated in tools/send_message_tool.py (38 refs) and hermes_cli/gateway.py (20 refs).

What moves

All .py files under gateway/ move to hermes_agent/gateway/ preserving directory structure (~48 files including platforms/, builtin_hooks/ subdirectories).

Import rewrites

Internal: all gateway.* → hermes_agent.gateway.*

External callers (68 prod refs):

• tools/send_message_tool.py (38 refs)
• hermes_cli/gateway.py (20 refs)
• agent/ (2 refs)
• hermes_agent/cron/ (4 refs — already moved, rewrite in this PR)

Test files: ~1,224 import refs across tests/gateway/ (~178 test files)

Also rewrites in this PR

• hermes_agent/cron/ files that import from gateway.* — these lines were left as-is in PR 2 because gateway hadn't moved yet. This is the expected one-time rewrite.

pyproject.toml changes

• REMOVE gateway, gateway.* from packages.find include

Non-.py files to check

• scripts/hermes-gateway (no extension) — has from gateway.run import start_gateway

Verification

rg "from gateway[\. ]" --type py       # should return 0
rg "import gateway\b" --type py        # should return 0
pytest