fix(MemoryGraph): first-wins on duplicate KNOWLEDGE slugs (drop UsageGraphError crash)

[Luo0oo]

Bug

buildGraph at LifeOS/install/LifeOS/TOOLS/MemoryGraph.ts:288 iterates KNOWLEDGE domains (People/Companies/Ideas/Research) and derives node IDs from bare filenames:

const slug = entry.replace(/\.md$/, "");
raws.push({ node: { id: slug, silo: "knowledge", ... } });

No domain prefix, so any two files sharing a basename across domains produce identical IDs. The second graph.addNode(node.id, ...) throws:

UsageGraphError: Graph.addNode: the "synthesis" node already exist in the graph.
    at addNode (…/graphology.mjs:3708:11)
    at buildGraph (…/MemoryGraph.ts:288:11)

The crash blocks the whole build. graph.json never regenerates, PATTERNS.md stays stale, Pulse's /api/memory/graph route silently serves nothing.

Fix

Guards graph.addNode with hasNode, matching the existing first-wins semantics of the bareToId population two lines below (if (!bareToId.has(bare)) bareToId.set(...)).

Emits console.warn listing the kept-path and skipped-path so users notice the data loss. MemoryGraph.ts is a report-generator tool with multi-line human output, not a scriptable pipe; a silent drop would hide files the user wrote.

Reproducer

mkdir -p ~/.claude/LIFEOS/MEMORY/KNOWLEDGE/{Companies,Research}
printf '%s\n' '---' 'title: A' '---' 'body' > ~/.claude/LIFEOS/MEMORY/KNOWLEDGE/Companies/foo.md
printf '%s\n' '---' 'title: B' '---' 'body' > ~/.claude/LIFEOS/MEMORY/KNOWLEDGE/Research/foo.md
bun ~/.claude/LIFEOS/TOOLS/MemoryGraph.ts build
# crashes without this fix
# With this fix: builds cleanly, prints:
# [MemoryGraph] slug collision: kept .../Companies/foo.md, skipped .../Research/foo.md

Orthogonal issues noticed (out of scope — worth separate PRs)

• KNOWLEDGE-first ordering in ingest() means WORK ISAs lose bare-slug wikilink resolution when a KNOWLEDGE file shares the basename
• patterns command rebuilds only on 60-min cache age, never checks source file mtimes — edit a note, get stale patterns silently
• addEdge widens weight on collision but never upgrades kind (a later related edge over an earlier tag keeps kind tag — provenance loss)

Verify

Reproducer above passes with this diff applied. Existing populated KNOWLEDGE trees without collisions are unchanged (the guard is a no-op path).