feat!: move to the alpha track — DSH 0.1.2-alpha.x only (v0.18.0-alpha.0)

DSH itself is still on its 0.1.2-alpha line (npm `alpha` dist-tag), so the
plugin mirrors it: v0.18.0-alpha.0 publishes under the npm `alpha`
dist-tag and supports DSH 0.1.2-alpha.x only. Stable-DSH (0.1.0-rc.8 ~
0.1.1-rc.2) users stay on v0.17.1 (npm `latest`). Verified end-to-end
against a real 0.1.2-alpha.2 host: full vitest suite, typecheck,
build/pack, consumer type surface, and the headless mount smoke 14/14
(the prerelease version also passes `dsh plugin add file:`).

- peer floor raised `^0.1.0-rc.8` -> `^0.1.2-alpha.2` (the mount install
  no longer warns: the old floor could not semver-match a prerelease
  host); dsh.plugin.json engines.dsh `>=0.1.2-alpha.2`.
- Dropped the pre-alpha compatibility layer:
  - e2e host RPC collapsed from the dot/slash dual dialect to slash-only
    (rpcAttempt; the 404-probe negotiation and its cache are gone), and
    parseLaunchUrl now requires the ?token= launch URL;
  - MarkdownText labels collapsed to the nested single shape (the cast
    became unnecessary against the alpha.2 declarations);
  - the defunct `@deepseek-ai/dsh-client-runtime` row is gone from the
    chunk externals allowlist (chunk-loader / tsdown / two specs) and
    from dsh.client.inject.
- market-manifest guard now allows an exact prerelease version (alpha
  cuts are not the market's verified `latest` target); release.yml picks
  the npm dist-tag from the version (prerelease -> `alpha`, else
  `latest`) so an alpha can never hijack `latest`.
- Docs retargeted: AGENTS.md §2/§3, README/README_EN badges + v0.18.0
  -alpha.0 section + install note (`dsh-better-sidebar@alpha`), guide.

src/client/markdown-labels.tsx

@@ -1,52 +1,31 @@
 /**
- * Copy-button / chrome labels for DSH's shared `MarkdownText`, shaped for
- * BOTH prop generations the plugin supports:
- *
- * - 0.1.1-rc.x: optional flat prop `codeLabels` — the renderer reads
- *   `labels.copyLabel` / `labels.copiedLabel` directly.
- * - 0.1.2-alpha.1+: renamed to a REQUIRED `labels` prop with a nested shape
- *   (`labels.code.copyLabel` + a screen-reader-only `labels.footnotes`
- *   heading). Passing only the old prop crashes the fence render with
- *   "Cannot read properties of undefined (reading 'code')" — the exact
- *   regression the mount lane caught on a real 0.1.2-alpha.1 host.
- *
- * The union object satisfies both readers, and {@link markdownTextProps}
- * passes it under BOTH prop names — each host ignores the one it does not
- * know. `footnotes` is left empty (the heading is sr-only; give it a real
- * string only if a locale key ever earns its place in all 19 dictionaries).
+ * Copy-button / chrome labels for DSH's shared `MarkdownText` (DSH
+ * 0.1.2-alpha contract): the renderer takes a REQUIRED nested `labels` prop
+ * — `labels.code.copyLabel` / `labels.code.copiedLabel` for the fence copy
+ * buttons plus a screen-reader-only `labels.footnotes` heading — and the
+ * MarkdownText/CodeBlock are cordis-free, falling back to HARDCODED Chinese
+ * when the labels are omitted, so every render site threads the plugin
+ * dictionary's localized pair through here (re-evaluated per render).
+ * `footnotes` is left empty (the heading is sr-only; give it a real string
+ * only if a locale key ever earns its place in all 19 dictionaries).
  */
 import type { ComponentProps } from 'react'
 import { MarkdownText } from '@deepseek-ai/dsh-client-ui-primitives'
 
-/** The flat copy-button pair the plugin threads through its own props
- *  (e.g. MermaidMarkdownProps.codeLabels — the chunk contract stays put). */
+/** The flat copy-button pair the plugin threads through its own props (e.g.
+ *  MermaidMarkdownProps.codeLabels — the chunk contract stays put). */
 export interface MarkdownCopyLabels {
   copyLabel: string
   copiedLabel: string
 }
 
-/** The dual-generation chrome labels object (see module doc). */
-export interface MarkdownChromeLabels extends MarkdownCopyLabels {
-  /** 0.1.2-alpha.1+ nested reads. */
-  code: MarkdownCopyLabels
-  /** 0.1.2-alpha.1+ sr-only footnotes heading. */
-  footnotes: string
-}
-
-/** Build the dual-shape chrome labels from a flat copy-button pair. */
-export function markdownChromeLabels(labels: MarkdownCopyLabels): MarkdownChromeLabels {
+/** MarkdownText props carrying the nested chrome labels. */
+export function markdownTextProps(text: string, labels: MarkdownCopyLabels): ComponentProps<typeof MarkdownText> {
   return {
-    copyLabel: labels.copyLabel,
-    copiedLabel: labels.copiedLabel,
-    code: { copyLabel: labels.copyLabel, copiedLabel: labels.copiedLabel },
-    footnotes: '',
+    text,
+    labels: {
+      code: { copyLabel: labels.copyLabel, copiedLabel: labels.copiedLabel },
+      footnotes: '',
+    },
   }
 }
-
-/** MarkdownText props carrying the labels under BOTH prop names. The cast is
- *  load-bearing: the plugin builds against the 0.1.1-rc.x declaration, where
- *  `labels` does not exist yet (and vice versa on a 0.1.2-alpha.1+ host). */
-export function markdownTextProps(text: string, labels: MarkdownCopyLabels): ComponentProps<typeof MarkdownText> {
-  const chrome = markdownChromeLabels(labels)
-  return { text, codeLabels: chrome, labels: chrome } as unknown as ComponentProps<typeof MarkdownText>
-}