update: SessionId / SessionStart / SessionOrigin 等を Segment 系名称へ

- Type/Function/Variantを Segment* 系へ統一
  - SessionId/SessionStart/SessionOrigin/SessionStartState/SessionState/SessionLogSink/SessionLockInfo
  - new_session_id / session_id / create_session* / list_sessions / lookup_session / update_session / find_by_session
  - protocol Event::SessionRotated → SegmentRotated、CompactDone.new_session_id → new_segment_id
- Module: session_log → segment_log / session → segment (file mv 含む)
  pod 側の session_log_sink → segment_log_sink も同様
- crate 名 (session-store)、CLI flag (--session)、ResumeWithSession (CLI tied) は据え置き
- session-tests/session_metrics_test 等の Store impl も追従

crates/memory/src/consolidate/input.rs

@@ -243,7 +243,7 @@ mod tests {
         let (_id, _) = write_staging(
             &layout,
             SourceRef {
-                session_id: "s".into(),
+                segment_id: "s".into(),
                 range: [0, 1],
             },
             ExtractedPayload::default(),

crates/memory/src/consolidate/lock.rs

@@ -260,7 +260,7 @@ mod tests {
         let (id_a, _) = write_staging(
             &layout,
             SourceRef {
-                session_id: "s".into(),
+                segment_id: "s".into(),
                 range: [0, 0],
             },
             ExtractedPayload::default(),
@@ -269,7 +269,7 @@ mod tests {
         let (id_b, _) = write_staging(
             &layout,
             SourceRef {
-                session_id: "s".into(),
+                segment_id: "s".into(),
                 range: [1, 1],
             },
             ExtractedPayload::default(),

crates/memory/src/consolidate/staging.rs

@@ -94,9 +94,9 @@ mod tests {
         ExtractedPayload::default()
     }
 
-    fn source(session_id: &str, range: [u64; 2]) -> SourceRef {
+    fn source(segment_id: &str, range: [u64; 2]) -> SourceRef {
         SourceRef {
-            session_id: session_id.into(),
+            segment_id: segment_id.into(),
             range,
         }
     }

crates/memory/src/consolidate/tidy.rs

@@ -305,7 +305,7 @@ mod tests {
     fn flags_sources_overflow() {
         let (dir, layout) = workspace();
         let many_sources: String = (0..15)
-            .map(|i| format!("  - session_id: s{i}\n    range: [{i}, {i}]\n"))
+            .map(|i| format!("  - segment_id: s{i}\n    range: [{i}, {i}]\n"))
             .collect();
         write(
             &dir.path().join(".insomnia/memory/decisions/big.md"),

crates/memory/src/extract/mod.rs

@@ -13,7 +13,7 @@
 //! （session-store の `LogEntry::Extension`、domain `"memory.extract"`）は
 //! Pod 側が責務を持つ。
 //!
-//! 出力 JSON の wrap は [`write_staging`] が `source: { session_id, range }`
+//! 出力 JSON の wrap は [`write_staging`] が `source: { segment_id, range }`
 //! を機械付与する形で担当し、LLM には source を推論させない。
 
 mod input;

crates/memory/src/extract/payload.rs

@@ -78,7 +78,7 @@ pub struct RequestEntry {
 
 /// staging に書き出される 1 ファイル分のレコード。
 ///
-/// `source` は Pod 側ラッパーが session_id と log entry range を
+/// `source` は Pod 側ラッパーが segment_id と log entry range を
 /// 機械付与する。LLM はこのフィールドを見ない / 推論しない。
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct StagingRecord {

crates/memory/src/extract/staging.rs

@@ -71,7 +71,7 @@ mod tests {
         let layout = WorkspaceLayout::new(tmp.path().to_path_buf());
 
         let source = SourceRef {
-            session_id: "sess-1".into(),
+            segment_id: "sess-1".into(),
             range: [3, 7],
         };
         let payload = ExtractedPayload {
@@ -93,7 +93,7 @@ mod tests {
 
         let written: StagingRecord =
             serde_json::from_str(&fs::read_to_string(&path).unwrap()).unwrap();
-        assert_eq!(written.source.session_id, "sess-1");
+        assert_eq!(written.source.segment_id, "sess-1");
         assert_eq!(written.source.range, [3, 7]);
         assert_eq!(written.payload.decisions.len(), 1);
     }
@@ -103,7 +103,7 @@ mod tests {
         let tmp = tempfile::TempDir::new().unwrap();
         let layout = WorkspaceLayout::new(tmp.path().to_path_buf());
         let source = SourceRef {
-            session_id: "sess".into(),
+            segment_id: "sess".into(),
             range: [0, 0],
         };
         let (_, path) = write_staging(&layout, source, ExtractedPayload::default()).unwrap();

crates/memory/src/schema/common.rs

@@ -10,7 +10,7 @@ pub use lint_common::Frontmatter;
 /// `last_sources` arrays for traceability back to raw session logs.
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct SourceRef {
-    pub session_id: String,
+    pub segment_id: String,
     /// `[start_entry, end_entry]` inclusive range of session-store entry indices.
     pub range: [u64; 2],
 }

crates/memory/src/tool/read.rs

@@ -60,7 +60,7 @@ impl Tool for ReadTool {
         })?;
 
         let text = String::from_utf8_lossy(&bytes).into_owned();
-        if let Some(session_id) = self.usage_session_id.as_deref() {
+        if let Some(segment_id) = self.usage_session_id.as_deref() {
             let usage_slug = params.slug.as_deref().unwrap_or("summary");
             let snapshot = usage::snapshot_record_from_bytes(
                 params.kind.record_kind(),
@@ -69,7 +69,7 @@ impl Tool for ReadTool {
             );
             if let Err(err) = usage::append_use_event(
                 &self.layout,
-                session_id.to_string(),
+                segment_id.to_string(),
                 UsageSource::MemoryRead,
                 vec![snapshot],
             ) {
@@ -140,9 +140,9 @@ pub fn read_tool(layout: WorkspaceLayout) -> ToolDefinition {
 
 pub fn read_tool_with_usage(
     layout: WorkspaceLayout,
-    session_id: impl Into<String>,
+    segment_id: impl Into<String>,
 ) -> ToolDefinition {
-    read_tool_inner(layout, Some(session_id.into()))
+    read_tool_inner(layout, Some(segment_id.into()))
 }
 
 fn read_tool_inner(layout: WorkspaceLayout, usage_session_id: Option<String>) -> ToolDefinition {

crates/memory/src/usage.rs

@@ -64,7 +64,7 @@ impl UsageRecordSnapshot {
 pub struct UsageEvent {
     pub id: Uuid,
     pub occurred_at: DateTime<Utc>,
-    pub session_id: String,
+    pub segment_id: String,
     pub event: UsageEventKind,
     pub source: UsageSource,
     pub records: Vec<UsageRecordSnapshot>,
@@ -72,7 +72,7 @@ pub struct UsageEvent {
 
 impl UsageEvent {
     pub fn new(
-        session_id: impl Into<String>,
+        segment_id: impl Into<String>,
         event: UsageEventKind,
         source: UsageSource,
         records: Vec<UsageRecordSnapshot>,
@@ -80,7 +80,7 @@ impl UsageEvent {
         Self {
             id: Uuid::now_v7(),
             occurred_at: Utc::now(),
-            session_id: session_id.into(),
+            segment_id: segment_id.into(),
             event,
             source,
             records,
@@ -144,7 +144,7 @@ pub fn append_usage_event(layout: &WorkspaceLayout, event: &UsageEvent) -> io::R
 /// Convenience for a successful explicit record read.
 pub fn append_use_event(
     layout: &WorkspaceLayout,
-    session_id: impl Into<String>,
+    segment_id: impl Into<String>,
     source: UsageSource,
     records: Vec<UsageRecordSnapshot>,
 ) -> io::Result<()> {
@@ -153,14 +153,14 @@ pub fn append_use_event(
     }
     append_usage_event(
         layout,
-        &UsageEvent::new(session_id, UsageEventKind::Use, source, records),
+        &UsageEvent::new(segment_id, UsageEventKind::Use, source, records),
     )
 }
 
 /// Convenience for resident model-invocation exposure cost telemetry.
 pub fn append_resident_exposure_event(
     layout: &WorkspaceLayout,
-    session_id: impl Into<String>,
+    segment_id: impl Into<String>,
     records: Vec<UsageRecordSnapshot>,
 ) -> io::Result<()> {
     if records.is_empty() {
@@ -169,7 +169,7 @@ pub fn append_resident_exposure_event(
     append_usage_event(
         layout,
         &UsageEvent::new(
-            session_id,
+            segment_id,
             UsageEventKind::ResidentExposure,
             UsageSource::ResidentInjection,
             records,