Docs accuracy sweep: correct stale guides/reference/admin docs against current behaviour

Fanned-out verification of all ~35 economy-explorer docs against the current code (treasury/business/chestshop/treasury-api-plugin/treasury-rest-api + explorer app). Structurally clean (no dead links, no frontmatter defects). Corrected the substantive inaccuracies found:

Reload behaviour (HIGH, multiple files): docs claimed Treasury/Business/ChestShop need a restart with no live reload. In fact /treasury reload, /business reload, and /csVersion reload (alias /chestshop reload) all re-read config.yml live. Fixed admin/configuration.md (3 rows), admin/config-treasury.md, admin/config-business.md, admin/config-chestshop.md.

Permission defaults backwards (HIGH): reference/business.md said every node except business.pay is operator-only; actually almost all business.* default true, only business.admin.* and business.tax.exempt default op. Rewritten.

/eco vs /economy (HIGH): reference/treasury.md claimed /eco "also answers to /economy"; /economy is a separate read-only stats command. Fixed + documented /economy and /sales.

Government account VIEWER tier (MED, several files): the read-only viewer account-access tier (PAR-237) was missing from reference/treasury.md, admin/government-accounts.md, concepts/accounts-and-money.md, concepts/glossary.md, concepts/permissions-and-roles.md. Added — with per-account-type accuracy (firm: member=see, authorizer=spend, owner manages; government: viewer=read, member=spend, authorizer=manages). NB: distinct from the new site-wide explorer viewer role (PAR-265) — disambiguated in the glossary.

Other: ChestShop free shops are disabled (ALLOW_FREE_SHOPS off) — removed free price option; SHIFT_SELLS_IN_STACKS is off by default — removed the shift-stack claim; op-default permission rows corrected. Gov guide overstated authorizer powers (auth mgmt is treasury.gov.admin; member/viewer mgmt is treasury.gov.account.manage). Added /fine firm, /business sales + chat, salary AFK-skip, fines webhook, sales config section. Added Webhooks to the Overview, Glossary to Concepts landing, /treasuryapi ui sync note. Fixed DocsSidebar nav drift (admin sidebar omitted government-accounts/configuration/webhooks).

Verified: typecheck + lint green.