fix(ui): drop dead internal pointers from the user-visible copy

[argszero]

Summary

Six user-visible strings still point at material that the 2026-08-22 docs flattening (6d87213, #119) deleted from this repo:

carrier	pointer	referent at HEAD
i18n.js wallet.raise.sub (zh+en) + its index.html fallback	（US-20）	docs/user-stories.md defines no US-<n> ids
i18n.js admin.raise.sub (zh+en) + its index.html fallback	（US-20：…）	same
i18n.js mk.detail.routeVal (zh+en)	（架构 v0.2 路由策略）	docs/architecture.md has no v0.2 section

#119 ("concise current-state docs") rewrote both user-facing docs: it dropped every US-<n> id from docs/user-stories.md and deleted the 4.2.1 路由与故障转移策略（v0.2） section from docs/architecture.md. Verified from the commit diff (- **US-20** 作为企业成员…, -#### 4.2.1 路由与故障转移策略（v0.2…).

The pointer shapes audited so far stop short of this one: #179 repointed the dangling §N references, #216 the file:line citations. The name + stamp shape (US-20, v0.2) was never audited — and these are the only user-visible carriers of one, since every other US- id in the repo sits in a code comment or in ui/README.md.

Related Issue

None — filed from a recon sweep of the i18n copy carriers.

Changes

• ui/js/i18n.js — drop the dead parentheticals from 6 live pack values (3 keys × zh/en). Each sentence was already self-contained.
• ui/index.html — keep the two edited data-i18n fallbacks byte-equal to their pack value (the fallback is a second source of truth; fix(ui): replace code identifiers in the English stat-card copy #168 had to touch both files for the same reason), and bump i18n.js?v=20260912-5 → 20260914-4.
• ui/README.md — re-point the 3 lines that cited 「架构 v0.2 路由策略」 at the section that carries that content today, docs/architecture.md §3 module table (router.rs row), noting the old v0.2 / 4.2.1 provenance as docs: repoint 5 dangling section references to their current sections #179 did.
• Deliberately not touched: the same-shaped stamps in admin.raise.demo / admin.org.demo / ops.demo (P2-C) — those keys are orphans, never rendered — and every US-/rant id inside comments, which is where the author keeps them.

Tests

• cargo test — 226 passed (unchanged; the i18n gate still sees 786/786 keys)
• cargo fmt --check / cargo clippy — no Rust file touched
• Instrument c2106_dead_pointer_probe.py (21 assertions: 6 pack values, both fallbacks, fallback↔pack parity, prose preserved, pack counts, plus two positive controls proving the referents really are absent from docs/) — pre-change tree 8 red → post-change 21/21 green
• 4 mutation legs on tree copies (host tree untouched), each flipping a distinct red set: re-insert zh US-20 → {C3, C7}; re-insert en v0.2 → {C4}; re-insert the stamp in the html fallback only → {C7, C7b}; revert one README re-point → {C17, C17b}

Checklist

• Branch name follows the convention (fix/)
• Commit message uses Conventional Commits
• Single responsibility, minimal diff (3 files, +12/−12, ui/ text only)