Update the assets skill's SEP-41 transfer and symbol type summaries #180

Finding

The assets skill's “SAC vs Custom Token Interface” list gives two incorrect types.
transfer gives its destination as Address; SEP-41 now declares MuxedAddress.
symbol() gives its return type as Symbol; SEP-41 declares String.
These declarations mislead readers implementing the interface or decoding token metadata.

Evidence

The ordinary published skill URL and its canonical source contain both entries.
The current SEP-41 specification and Soroban SDK 27.0.6 agree on the replacement
types. transfer_from still uses an Address destination.

The neighboring Rust client example is valid: the generated client accepts
conversion into MuxedAddress, including an &Address. An isolated compile of
that exact call passed. This finding does not request an explicit conversion in
the example or claim that existing Address callers fail.

Additional recorded evidence:

• 2026-11-06T17:56:09Z GET https://skills.stellar.org/skills/assets/SKILL.md returned HTTP 200, SHA-256 ead389a330f0dc57da419fa31d40fa7177f498e60c50f1433b10a1604373c5a8. Lines 380 and 385 list an Address-only transfer destination and a Symbol return type for symbol().
• Canonical source: https://raw.githubusercontent.com/stellar/stellar-dev-skill/248c4caeeb8d8c149ed0a8ae05e5725aa0cd9d29/skills/assets/SKILL.md, Git blob 1658bebe308055e105cfedf7fcd9f6f1ba478a7b. The same blob is in Raven's frozen skill inventory.
• https://raw.githubusercontent.com/stellar/stellar-protocol/ced008c3727005ca4a775f430fe6fe346c30f58f/ecosystem/sep-0041.md declares transfer destination MuxedAddress and symbol() return String. Its destination documentation explicitly permits MuxedAddress or Address.
• https://docs.rs/soroban-sdk/27.0.6/src/soroban_sdk/token.rs.html declares the same interface types. The generated TokenClient accepts an Into destination.
• The skill's existing token.transfer(&from, &to, &amount) example passed cargo check --offline against soroban-sdk =27.0.6. The client example is valid and is not part of this defect.
• Dedupe checked all 46 repository issues and 130 PRs on 2026-11-06. The earlier MuxedAddress guidance change affected smart-contracts/development.md, not this assets interface list. No duplicate active or resolved Raven skill finding was found.

Recommendation

Update the two interface-list entries to match SEP-41. Briefly distinguish the
interface parameter from the generated client's accepted conversions. Keep the
working &to client example and the separate transfer_from destination type.

Source Record

Raven recorded this finding as sk-039 (skills, discovered 2026-11-06).

Public source record: improvements/skills/sk-039-assets-token-interface-types.md

Immutable source snapshot: 2bcecb740d88

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