fix: patterns ignore project scope and never decay

[CalebisGross]

Problem

Two related issues with the pattern system:

1. Stale patterns persist at full strength

Patterns like "Redundant Memory Logging" (about PR #132, months old) and "Full-Stack Scientific AI Infrastructure Development" (molecular generation platform — not even this project) surface at strength 1.0 in every recall. They add noise to every response and there's no mechanism to decay, archive, or dismiss them.

2. Cross-project bleed

Recall scoped to project: mnemonic still surfaces patterns from Petra-PB, CannaSage, felixlm, and other projects. Pattern matching doesn't respect the project filter that memories correctly honor.

Expected

• Patterns should decay over time if their constituent memories are archived/fading
• Patterns should respect project scoping on recall
• There should be a way to archive/dismiss a pattern (MCP tool or API)

Impact

Every single recall response includes 5 patterns, and typically 2-3 are irrelevant noise from other projects or stale observations. This is the highest-noise component of recall output.

[CalebisGross]

Fixed in PR #311 — three changes:

• Pattern embedding search now scopes by project in SQL (no more cross-project bleed)
• Decay: self-sustaining immunity requires healthy evidence (≥50% active), evidence-based decay applies regardless of access recency, fading→archived transition at strength <0.05
• New dismiss_pattern MCP tool + ArchivePattern store method for manual cleanup