feat: add skills system with weather, daily-briefing, and skill-creator

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

main/agent/context_builder.c

@@ -1,6 +1,7 @@
 #include "context_builder.h"
 #include "mimi_config.h"
 #include "memory/memory_store.h"
+#include "skills/skill_loader.h"
 
 #include <stdio.h>
 #include <string.h>
@@ -59,11 +60,10 @@ esp_err_t context_build_system_prompt(char *buf, size_t size)
         "- Use get_current_time to know today's date before writing daily notes.\n"
         "- Keep MEMORY.md concise and organized — summarize, don't dump raw conversation.\n"
         "- You should proactively save memory without being asked. If the user tells you their name, preferences, or important facts, persist them immediately.\n\n"
-        "## Heartbeat\n"
-        "The file /spiffs/config/HEARTBEAT.md contains periodic tasks.\n"
-        "When triggered by heartbeat, read the file and execute any pending tasks.\n"
-        "If nothing needs attention, reply with just: HEARTBEAT_OK\n"
-        "You can also write to HEARTBEAT.md to schedule tasks for yourself.\n");
+        "## Skills\n"
+        "Skills are specialized instruction files stored in /spiffs/skills/.\n"
+        "When a task matches a skill, read the full skill file for detailed instructions.\n"
+        "You can create new skills using write_file to /spiffs/skills/<name>.md.\n");
 
     /* Bootstrap files */
     off = append_file(buf, size, off, MIMI_SOUL_FILE, "Personality");
@@ -81,6 +81,16 @@ esp_err_t context_build_system_prompt(char *buf, size_t size)
         off += snprintf(buf + off, size - off, "\n## Recent Notes\n\n%s\n", recent_buf);
     }
 
+    /* Skills */
+    char skills_buf[2048];
+    size_t skills_len = skill_loader_build_summary(skills_buf, sizeof(skills_buf));
+    if (skills_len > 0) {
+        off += snprintf(buf + off, size - off,
+            "\n## Available Skills\n\n"
+            "Available skills (use read_file to load full instructions):\n%s\n",
+            skills_buf);
+    }
+
     ESP_LOGI(TAG, "System prompt built: %d bytes", (int)off);
     return ESP_OK;
 }