worker: add session reference view

.yoi/tickets/00001KXS56AS5/item.md

@@ -1,9 +1,11 @@
 ---
 title: 'Session reference viewを共通基盤として実装する'
-state: 'ready'
+state: 'closed'
 created_at: '2026-07-17T23:04:40Z'
-updated_at: '2026-07-17T23:20:00Z'
+updated_at: '2026-07-17T23:27:20Z'
 assignee: null
+queued_by: 'yoi ticket'
+queued_at: '2026-07-17T23:15:15Z'
 ---
 
 ## 背景

.yoi/tickets/00001KXS56AS5/resolution.md

@@ -0,0 +1,11 @@
+Implemented `SessionReferenceView` common substrate.
+
+The Worker crate now has an immutable session reference view that can build User/Assistant overview items, index user/assistant/system/tool references, search with kind and tool input/output filters, perform bounded reads with truncation metadata, and resolve source refs for future extract staging anchors. Compaction search now uses this common view; read-session behavior remains unchanged for compatibility.
+
+Validation passed:
+- `cargo fmt --check`
+- `cargo test -p worker session_reference`
+- `cargo test -p worker compact::worker`
+- `cargo test -p worker`
+- `cargo test -p memory`
+- `nix build .#yoi`

.yoi/tickets/00001KXS56AS5/thread.md

@@ -4,4 +4,84 @@
 
 LocalTicketBackend によって作成されました。
 
+---
+
+<!-- event: state_changed author: "yoi ticket" at: 2026-07-17T23:15:15Z from: ready to: queued reason: queued field: state -->
+
+## State changed
+
+Ticket を `yoi ticket` が queued にしました。
+
+
+---
+
+<!-- event: state_changed author: "yoi ticket" at: 2026-07-17T23:15:15Z from: queued to: inprogress reason: cli_state field: state -->
+
+## State changed
+
+State changed to `inprogress`.
+
+
+---
+
+<!-- event: implementation_report author: hare at: 2026-07-17T23:27:20Z -->
+
+## Implementation report
+
+Implemented `SessionReferenceView` common substrate.
+
+Changes:
+- Added `crates/worker/src/session_reference.rs` with immutable view construction over a session history slice.
+- The view produces User/Assistant overview items and a searchable evidence index over user/assistant/system/tool references.
+- Added text search with `kind` filter and tool input/output/both filtering via `tool_part`.
+- Added bounded read by id or `entry_range` with truncation metadata.
+- Added source-ref resolution by evidence id for future extract staging anchors.
+- Rewired compaction `search_session_log` to search through `SessionReferenceView` while leaving `read_session_items` behavior unchanged for now.
+
+Validation:
+- `cargo fmt --check`
+- `cargo test -p worker session_reference`
+- `cargo test -p worker compact::worker`
+- `cargo test -p worker`
+- `cargo test -p memory`
+- `nix build .#yoi`
+
+
+---
+
+<!-- event: state_changed author: "yoi ticket" at: 2026-07-17T23:27:20Z from: inprogress to: done reason: cli_state field: state -->
+
+## State changed
+
+State changed to `done`.
+
+
+---
+
+<!-- event: state_changed author: hare at: 2026-07-17T23:27:20Z from: done to: closed reason: closed field: state -->
+
+## State changed
+
+Ticket を closed にしました。
+
+
+---
+
+<!-- event: close author: hare at: 2026-07-17T23:27:20Z status: closed -->
+
+## 完了
+
+Implemented `SessionReferenceView` common substrate.
+
+The Worker crate now has an immutable session reference view that can build User/Assistant overview items, index user/assistant/system/tool references, search with kind and tool input/output filters, perform bounded reads with truncation metadata, and resolve source refs for future extract staging anchors. Compaction search now uses this common view; read-session behavior remains unchanged for compatibility.
+
+Validation passed:
+- `cargo fmt --check`
+- `cargo test -p worker session_reference`
+- `cargo test -p worker compact::worker`
+- `cargo test -p worker`
+- `cargo test -p memory`
+- `nix build .#yoi`
+
+
 ---