fix: eliminate dead export false positives

[bntvllnt]

Summary

Fixes #6 — find_dead_exports had ~33% false positive rate (2/6). Two root causes:

• Duplicate imports dropped: second import to same target silently skipped due to graphology's single-edge constraint, losing symbols (e.g., import type {SearchIndex} after import {createSearchIndex, ...})
• Same-file calls invisible: parser excluded intra-file calls, analyzer only checked import edges — so registerTools() called within startMcpServer() was flagged dead

Changes

File	Change
src/graph/index.ts	Merge duplicate edge symbols into existing edge (both graphology attrs + edges[] array)
src/parser/index.ts	Remove declRelPath !== callerFile guard — include same-file calls in callSites
src/analyzer/index.ts	Integrate call graph edges into consumed symbols check + class method normalization (ClassName.method → ClassName)
src/analyzer/index.test.ts	7 regression tests

Semantics change

• Old: dead = "no external file imports this symbol"
• New: dead = "no import edges AND no call edges reference this symbol (including same-file)"

Verification

Self-analysis after fix:

• SearchIndex — NOT flagged dead (was false positive)
• registerTools — NOT flagged dead (was false positive)
• tokenize — NOT flagged dead (same-file call by createSearchIndex)
• detectEntryPoints — NOT flagged dead (same-file call by traceProcesses)

Test plan

• 7 new regression tests (truly dead, type-only imports, duplicate merge, same-file calls, class methods, mixed dead/alive, edge merge sync)
• All 185 tests pass (178 existing + 7 new)
• Lint, typecheck, build all green
• Self-analysis: 0 false positives on known cases