feat(statics): add testToken (SOL) to BitGoJS statics

[bitgo-ai-agent-dev]

What

• Add tsol:testtoken and sol:testtoken entries to the UnderlyingAsset enum in modules/statics/src/base.ts
• Add tsolToken() entry for the on-chain SPL token in modules/statics/src/coins/solTokens.ts (UUID fcb25a47, mint So111...112, 9 decimals, standard Token Program)
• Add ofcsolToken() entry for the OFC coin in modules/statics/src/coins/ofcCoins.ts (UUID 4b17b883, name ofc:sol:testtoken, 9 decimals)

Why

• Required to onboard testToken (SOL) across the BitGo ecosystem as part of the token onboarding workflow validation (SCAAS-10507). This is a dry-run/test token used to validate the Linear ticket execution route; the contract address is the well-known Wrapped SOL mint reused as a placeholder — not a real deployment.

Decision log

1. sol:testtoken added alongside tsol:testtoken: The OFC factory ofcsolToken() references an UnderlyingAsset['sol:...'] key (mainnet-style), matching the pattern of ofcsol:bils → sol:bils and ofcsol:tshvontesting → sol:tshvontesting. Since this test-only token had no mainnet entry, sol:testtoken was added per ticket instructions (step 3 note).

2. ofcsolToken used (not tofcsolToken): The ticket explicitly prescribes ofcsolToken with name ofc:sol:testtoken. While some existing test OFC SOL tokens use tofcsolToken with ofctsol: prefix (e.g. ttkb), there is also a precedent for ofcsolToken with test/staging tokens that live on the SOL mainnet chain config (e.g. ofcsol:tshvontesting). Followed the ticket's explicit instruction.

3. OFC name ofc:sol:testtoken vs conventional ofcsol:testtoken: The ticket explicitly prescribes ofc:sol:testtoken. This deviates from the ofcsol: prefix convention used by other entries. Followed the ticket as-written since this is a dry-run; flagging in open questions below.

Test plan

• TypeScript compilation passes (npx tsc --noEmit) with no errors
• Only three files modified: base.ts, solTokens.ts, ofcCoins.ts
• Only additions — no existing entries modified or removed

Open questions

1. OFC name format: The ticket prescribes ofc:sol:testtoken but the existing convention for ofcsolToken() entries uses ofcsol:<token> (e.g. ofcsol:bils). Should this use ofcsol:testtoken instead? The name.replace(/^ofc/, '') suffix derivation in ofc.ts:394 would produce :SOL:TESTTOKEN with a leading colon for the prescribed name. This appears to be a ticket authoring issue — please confirm the intended name before merging.

Ticket: SCAAS-10508

[linear-code]

SCAAS-10508

[bitgo-ai-agent-dev]

@claude please review this PR