fix(config): use is_truthy_value() for config boolean parsing across 8 paths

[ryptotalent]

Summary

Several config boolean reads used raw bool() coercion on values from config.yaml. In Python, every non-empty string is truthy, so quoted false-like values ("false", "0", "off") were silently treated as enabled.

This is the same bug class as #49883 (voice.beep_enabled), but affecting 8 config paths across the codebase. This PR fixes all of them by replacing bool(cfg.get(...)) with the shared is_truthy_value() parser.

Root Cause

Python's bool() treats any non-empty string as True:

bool("false")  # → True  (wrong!)
bool("0")      # → True  (wrong!)
bool("off")    # → True  (wrong!)

The project already has is_truthy_value() in utils.py that correctly handles the TRUTHY_STRINGS frozenset (1, true, yes, on) and treats all other strings as False. Several call sites were not using it.

Affected Config Paths

File	Config Path	Impact
agent/curator.py	curator.enabled	Curator runs even when disabled
agent/curator.py	curator.prune_builtins	Built-in skills pruned even when disabled
agent/curator.py	curator.consolidate	Skill consolidation runs even when disabled
agent/curator_backup.py	curator.backup.enabled	Backups skip even when enabled
agent/lsp/manager.py	lsp.enabled	LSP runs even when disabled
hermes_cli/webhook.py	webhook.enabled	Webhooks active even when disabled
hermes_cli/kanban_decompose.py	kanban.auto_promote_children	Auto-promotion runs even when disabled
hermes_cli/cli_commands_mixin.py	display.runtime_footer.enabled	Footer shows even when disabled
agent/agent_init.py	sessions.write_json_snapshots	JSON snapshots written even when disabled

Fix

Replace all bool(cfg.get("key", default)) with is_truthy_value(cfg.get("key"), default=default). This is the same pattern already used in agent/agent_init.py (line 1348), hermes_cli/tools_config.py, hermes_cli/auth.py, and other files that correctly parse config booleans.

Test Plan

• Added 10 regression tests in test_config_truthy_parsing.py covering quoted "false", "0", "off", "true", and missing-key defaults
• All 10 new tests pass
• Existing curator tests pass (9/9)
• Existing auxiliary_client tests pass (72/72)

Closes #49883