🐛 chore(spawn/templates/agent_mock_branch): remove deprecated modules and tests

- delete all deprecated aipass modules: api, assistant, citizenship, devpulse,
  drone, flow, mail, seedgo, skills, trigger, templates, and tests
- remove seedgo config and coverage files no longer used
- cleanup tests for drone CLI, compliance, core, integration, modules, phase2,
  seedgo CLI, core, plugins, silent failure detection, file module size, paths,
  and version to reduce maintenance burden
- add new agent_mock_branch spawn template with scaffold files, config, and
  verification tool for branch consistency checks
- add comprehensive .registry_ignore.json and .backup_ignore.json to exclude
  unwanted files from branch updates and backups
- include branch README, artifacts, docs, logs, pytest setup, tools, tests, and
  standard bypass configs for new agent mock branch template
- rename and reorganize template files from branch_template to spawn/templates
  agent.template for consistent naming and usage

src/aipass/api/__init__.py

@@ -1,5 +0,0 @@
-"""aipass.api — LLM access, model routing, and agent spawning.
-
-Unified interface to language models. Handles API keys, model selection,
-rate limiting, and spawning agent processes.
-"""

src/aipass/api/handlers/__init__.py

@@ -1 +0,0 @@
-"""api.handlers — API client implementation and rate limiting."""

src/aipass/api/modules/__init__.py

@@ -1 +0,0 @@
-"""api.modules — Model routing and client logic."""

src/aipass/api/plugins/__init__.py

@@ -1 +0,0 @@
-"""api.plugins — Extensible plugin interface."""