Fix truncation issues in piplan, SQLite storage, and history compression; add PIPlanMaxChars configuration

internal/config/config.go

@@ -18,6 +18,7 @@ type Config struct {
 	ReactMaxSteps           int
 	ToolCallTimeoutSec      int
 	ToolOutputMaxChars      int
+	PIPlanMaxChars          int // PI 规划工具专用输出上限，独立于 TOOL_OUTPUT_MAX_CHARS
 	EnableCapabilityGap     bool
 	AutoSkillDir            string
 	GapDraftTriggerCount    int
@@ -95,6 +96,7 @@ func Load() (Config, error) {
 		ReactMaxSteps:           intFromEnv("REACT_MAX_STEPS", 0),
 		ToolCallTimeoutSec:      intFromEnv("TOOL_CALL_TIMEOUT_SEC", 15),
 		ToolOutputMaxChars:      intFromEnv("TOOL_OUTPUT_MAX_CHARS", 4000),
+		PIPlanMaxChars:          intFromEnv("PI_PLAN_MAX_CHARS", 40000),
 		EnableCapabilityGap:     boolFromEnv("ENABLE_CAPABILITY_GAP", true),
 		AutoSkillDir:            defaultIfEmpty(os.Getenv("AUTO_SKILL_DIR"), filepath.Join(agentWorkspaceDir, "skills")),
 		GapDraftTriggerCount:    intFromEnv("GAP_DRAFT_TRIGGER_COUNT", 3),
@@ -157,6 +159,9 @@ func Load() (Config, error) {
 	if cfg.ToolOutputMaxChars < 256 || cfg.ToolOutputMaxChars > 200000 {
 		return Config{}, fmt.Errorf("TOOL_OUTPUT_MAX_CHARS must be between 256 and 200000")
 	}
+	if cfg.PIPlanMaxChars < 1000 || cfg.PIPlanMaxChars > 500000 {
+		return Config{}, fmt.Errorf("PI_PLAN_MAX_CHARS must be between 1000 and 500000")
+	}
 	if cfg.GapDraftTriggerCount < 1 || cfg.GapDraftTriggerCount > 100 {
 		return Config{}, fmt.Errorf("GAP_DRAFT_TRIGGER_COUNT must be between 1 and 100")
 	}