feat(ITC-WP-0016): establish PracticePattern language

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a025c2-407a-7a32-b40a-f37a52f03f62

infospace/agent/briefs/practice-pattern-interface-deprecation-strangler.md

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+---
+id: agent-brief/practice-pattern-interface-deprecation-strangler
+artifact_id: practice-pattern/interface-deprecation-strangler
+source_path: patterns/InterfaceDeprecationStrangler.md
+source_kind: practice-pattern
+generated: true
+---
+
+<!-- GENERATED by info_tech_canon; do not edit by hand. -->
+
+# Agent Brief: InterfaceDeprecationStrangler
+
+- Artifact ID: `practice-pattern/interface-deprecation-strangler`
+- Kind: `practice-pattern`
+- Canonical path: `patterns/InterfaceDeprecationStrangler.md`
+- Full source: `patterns/InterfaceDeprecationStrangler.md`
+- Summary: Reusable canon PracticePattern: InterfaceDeprecationStrangler.
+
+## Retrieval Hints
+
+Imports and anchors:
+- `model/devsecops`
+- `model/governance`
+- `model/observability`
+- `scheme/practice-pattern`
+
+## Owned Concepts
+
+- `InterfaceDeprecationStrangler`
+
+## Related Distinctions
+
+- **Interface deprecation vs retirement vs removal**: Deprecation guides and observes callers, retirement ends legacy behavior while retaining a metered tombstone, and removal deletes that tombstone only after the evidence gate passes.