feat(notebook): rename ledger to notebook with subject-oriented grounding and add topic-awareness layerRefactor/notebook

[ofriw]

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Summary

This PR renames the ledger subsystem to notebook, upgrades its semantics from a sparse continuity cache to durable subject-oriented grounding, and introduces a topic-awareness layer that uses the active semantic frame to drive spawn-vs-handoff decisions with boundary detection.

What changed

Renamed ledger/ → notebook/ — the directory, state property (state.ledger → state.notebookPages), all public tools (ledger_add → notebook_write, ledger_get → notebook_read, ledger_list → notebook_index), and the interactive /ledger command → /notebook. Backward-compatible rehydration scans for both ledger-entry and notebook-entry persisted custom types, so no data loss across upgrades.

Semantic upgrade — the notebook is now framed as durable cross-context grounding organized by subject/thread, not a running stream-of-consciousness cache. The CONTEXT_PRIMER, tool descriptions, and prompt guidelines all steer toward pages that outlive a single session: architecture, decisions, constraints, open questions. Transient task state belongs in the handoff brief, not the notebook.

New topic-awareness layer — notebook/topic.ts + notebook/topic-tool.ts add an activeNotebookTopic field to state, a notebook_topic_set tool, and a pendingTopicBoundaryHint mechanism. When the topic changes, the watchdog emits a boundary nudge (even below the 30% context heuristic) recommending a deliberate handoff. The TUI shows the topic in the status bar (🧭 topic), and the high-context warning widget is now topic-aware. Handoff compaction automatically clears the active topic so the next context starts fresh.

Breaking changes

• All ledger public API symbols renamed: migrate any extension code or stored session references from ledger_* to notebook_* tool names.
• State shape: state.ledger → state.notebookPages (affects direct state access).
• /ledger TUI command renamed to /notebook; the command now also accepts a topic argument (/notebook <topic>) to set the active frame.
• The watchdog nudge format has changed: it no longer emits the old percent-only reminders and instead generates topic-aware guidance. Any code parsing nudge text programmatically will need updating.

Value

The rename signals a real semantic upgrade — the notebook is a carefully curated set of durable pages for cross-context reuse, not a firehose of continuity scribbles. The topic-awareness layer gives the agent a lightweight frame for context-boundary decisions: stay and spawn within a topic, handoff when the topic shifts. This directly reduces the amount of stale context dragged across job boundaries, and the boundary hint mechanism catches mid-task pivots that would otherwise silently degrade context quality.

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Attached is an agent optimized description of the changes in this PR - AGENT_REVIEW.md