fix(config): forgiving bool parsing for pre-existing feature flags

scheduler_prompt_injection, cache_warming_enabled, and headroom_enabled
used env_parse::<bool>, i.e. bool::from_str, which accepts only "true"/
"false". Any other truthy spelling (1/yes/on/TRUE) silently parsed to
false — the feature failed closed with no error or log. Switch them to
the same env_bool helper added for terminal capture so =1/yes/on now work
as operators expect. Backward compatible: true/false keep their meaning.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/colibri-daemon/src/config.rs

@@ -105,12 +105,11 @@ impl DaemonConfig {
             host,
             max_context_tokens: env_parse("COLIBRI_MAX_CONTEXT_TOKENS").unwrap_or(128_000),
             cost_mode: std::env::var("COLIBRI_COST_MODE").unwrap_or_else(|_| "smart".to_string()),
-            scheduler_prompt_injection: env_parse("COLIBRI_SCHEDULER_PROMPT_INJECTION")
-                .unwrap_or(false),
-            cache_warming_enabled: env_parse("COLIBRI_CACHE_WARMING").unwrap_or(false),
+            scheduler_prompt_injection: env_bool("COLIBRI_SCHEDULER_PROMPT_INJECTION"),
+            cache_warming_enabled: env_bool("COLIBRI_CACHE_WARMING"),
             cache_warming_interval_hours: env_parse("COLIBRI_CACHE_WARMING_INTERVAL_HOURS")
                 .unwrap_or(0),
-            headroom_enabled: env_parse("COLIBRI_HEADROOM_ENABLED").unwrap_or(false),
+            headroom_enabled: env_bool("COLIBRI_HEADROOM_ENABLED"),
             headroom_socket_path: std::env::var("COLIBRI_HEADROOM_SOCKET")
                 .map(PathBuf::from)
                 .unwrap_or_else(|_| PathBuf::from("/var/run/colibri/headroom.sock")),