feat: Soroban static rules for signature verification, auth in loops, recursive calls, and call depth (#899, #874, #878, #879)

[wowamaxe-glitch]

Summary of Changes

This Pull Request implements static analysis analyzers and rule definitions for four Soroban contract optimization issues on GasGuard:

1. Issue #899: Detect Duplicate Soroban Signature Verification

• Dataflow Analyzer: Added DuplicateSignatureAnalyzer (packages/analyzers/soroban/dataflow/duplicate-signature-analyzer.ts) to track signature verification calls (ed25519_verify, secp256k1_verify, verify_signature, signature.verify, check_auth) within function scopes and detect duplicate verifications executed on identical inputs.
• Rule Definition: Implemented detectDuplicateSignatureVerifications rule (packages/rules/soroban/src/authorization/duplicate-signature-verification-rule.ts) with severity 'high'|'medium'.

2. Issue #874: Detect Soroban Authorization Inside Expensive Loops

• Loop Analyzer: Added AuthorizationLoopAnalyzer (packages/analyzers/soroban/loops/authorization-loop-analyzer.ts) to inspect loop constructs (for, while, loop), detect authorization operations (require_auth, require_auth_for_args, verify_authorizations, invoker()) inside loops, estimate iteration cost impact, and suggest hoisting auth checks.
• Rule Definition: Implemented detectAuthorizationInLoops rule (packages/rules/soroban/src/authorization/authorization-in-loops-rule.ts).

3. Issue #878: Detect Recursive Soroban Contract Calls

• Call Graph Cycle Analyzer: Added RecursiveCallAnalyzer (packages/analyzers/soroban/callgraph/recursive-call-analyzer.ts) to construct function call graphs, detect direct self-recursion and indirect cyclic invocation paths, and report affected call cycles.
• Rule Definition: Implemented detectRecursiveContractCalls rule (packages/rules/soroban/src/calls/recursive-contract-calls-rule.ts).

4. Issue #879: Implement Soroban Call Depth Threshold Rule

• Call Depth Analyzer: Added CallDepthAnalyzer (packages/analyzers/soroban/callgraph/call-depth-analyzer.ts) to calculate maximum invocation depth per entrypoint with configurable depth threshold limits (default 3).
• Rule Definition: Implemented detectCallDepthThresholdExceeded rule (packages/rules/soroban/src/calls/call-depth-threshold-rule.ts).

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Verification

• Unit Tests: Added test suite packages/rules/soroban/tests/issues-899-874-878-879.spec.ts covering all 4 rules (8/8 tests passing, 19/19 soroban tests passing).

Closes #899
Closes #874
Closes #878
Closes #879

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[mijinummi]

Kindly fix conflict @wowamaxe-glitch

[wowamaxe-glitch]

@mijinummi Kindly Merge