zeph-context 0.20.1

# zeph-context

Context budget, lifecycle management, compaction strategy, and stateless context assembler for the
[Zeph](https://github.com/bug-ops/zeph) AI agent.

This crate contains the **stateless and data-only** parts of context management extracted from
`zeph-core`. It has no dependency on `zeph-core` — callers implement the `IndexAccess` trait and
populate `ContextMemoryView` before each assembly pass.

## Modules

- `budget` — `ContextBudget` and `BudgetAllocation` for token budget calculation
- `manager` — `ContextManager` state machine and `CompactionState` lifecycle tracking
- `assembler` — `ContextAssembler` parallel fetch coordinator; classifies each slot into a `TypedPage`, enforces per-type fidelity invariants at compaction boundaries, and emits a `CompactionAuditSink` record per compacted page
- `input` — `ContextAssemblyInput`, `ContextMemoryView`, `IndexAccess` trait
- `slot` — `ContextSlot`, `CompactionOutcome`, message-chunking helpers
- `typed_page` — `TypedPage` (BLAKE3 content-hash id), `PageType` enum (`ToolOutput`, `ConversationTurn`, `MemoryExcerpt`, `SystemContext`), per-type `PageInvariant` implementations, and `InvariantRegistry`
- `audit` — `CompactionAuditSink` — bounded async mpsc channel that records one audit entry per compacted page; consumers can drain it for observability or compliance logging
- `error` — `ContextError`

## ClawVM typed-page compaction

`ContextAssembler::gather()` classifies every context slot into a `TypedPage` keyed by a BLAKE3 content hash. Each `PageType` carries a `PageInvariant` that declares the minimum-fidelity guarantee for compaction:

| PageType | Invariant |
|----------|-----------|
| `ToolOutput` | Preserve tool name, return code, and first/last N bytes of output |
| `ConversationTurn` | Preserve role, first sentence, and any code blocks |
| `MemoryExcerpt` | Preserve entity names and relationship predicates |
| `SystemContext` | Never compact — always injected verbatim |

At every compaction boundary the invariant is checked before the LLM compaction call. If the post-compaction result would violate the invariant the compaction is rejected and the original content is retained.

## License

MIT OR Apache-2.0