feat(api): expand ExtendedAccount to all 65 on-chain fields

[ety001]

What

Expand ExtendedAccount (protocol/api/accounts.go) to carry all 65 keys a live condenser_api.get_accounts response returns, so steemdb-sync's account refresher can capture a complete account snapshot in a single decode.

Previously the struct covered only 51 fields (the original 8 conveyor-facing fields + 43 from the expansion spec). A real get_accounts(["steemit"]) returns 65 keys, matching steemd's condenser_api::api_account_object (58) + extended_account (7).

Why

steemdb-sync's golang account refresher needs the full chain state per account. The expansion spec's field list was missing 14 fields, and several of its type assumptions diverged from what the chain actually emits.

Changes

protocol/api/accounts.go

• New Manabar struct for voting_manabar / downvote_manabar (current_mana is a share_type string, last_update_time a uint32).
• ExtendedAccount extended to the full 65 fields, grouped: original subset, scalar strings, scalar bool/int, Manabar, share_type RawMessage, extended_account collections.
• Original 8 conveyor-facing fields unchanged (order / type / tag) — backward compatible.

Added fields (14)

id, savings_withdraw_requests, reward_sbd_balance, reward_steem_balance, reward_vesting_balance, reward_vesting_steem, transfer_history, market_history, post_history, vote_history, other_history, tags_usage, guest_bloggers (+ typed Manabar replacing the previous RawMessage manabar fields).

Type design — driven by on-chain reality

field(s)	Go type	reason
voting_manabar / downvote_manabar	Manabar	{current_mana:string, last_update_time:number}
withdrawn, to_withdraw, curation_rewards, posting_rewards, post_bandwidth	json.RawMessage	share_type serializes as string or number across nodes
proxied_vsf_votes	[]json.RawMessage	chain emits a mixed array, e.g. ["452574069424",0,0,0]
*_history, tags_usage, guest_bloggers	json.RawMessage	always [] on chain today; kept raw so a future fill (FC [[k,v],...]) won't break decode

Verification

• go build ./... ✅
• go vet ./protocol/api/... ✅
• go test ./... ✅ (all packages green, no regression)
• Script cross-check: the struct's json tags match the live response's 65 keys exactly — 0 missing, 0 extra.
• New TestUnmarshal_ExtendedAccount_FullFixture decodes a real 65-key snapshot and asserts representative fields from every group (including the mixed proxied_vsf_votes array and Manabar round-trip).

Note on the data path

condenser_api.get_accounts is not in jussi's special upstream/rewrite list — it is only TTL-cached, so the JSON the SDK sees is steemd's verbatim output. No jussi-side field changes to account for.

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Related: steemdb-sync account refresher.