fix(vscode): switch all 15 extensions to real mcpServerDefinitionProviders API

[acedatacloud-dev]

What

Replaces the broken VS Code extension manifest with a real, working one for
all 15 MCP marketplace extensions (mcp-suno, mcp-midjourney, …,
mcp-shorturl).

Why this is needed

The release shipped via PR #356 / #358 used contributes.mcpServers plus a
root-level contributes.inputs block. Neither is a valid VS Code
contribution point — VS Code parses the manifest, finds no recognised
contribution, and registers nothing.

User-visible symptom: install the extension → nothing happens. No token
prompt, no server in Configure Tools, no entry in the MCP tools panel.

Verified against:

• src/vs/workbench/contrib/mcp/common/mcpConfiguration.ts in
  microsoft/vscode — the only MCP extension point is
  mcpServerDefinitionProviders.
• vscode.d.ts confirms vscode.McpHttpServerDefinition,
  vscode.McpStdioServerDefinition,
  vscode.lm.registerMcpServerDefinitionProvider, and a
  resolveMcpServerDefinition hook for runtime auth.
• Downloaded acedatacloud.mcp-suno@2026.531.0 from the marketplace and
  confirmed the manifest VS Code receives is byte-identical to our broken
  one.
• Downloaded upstash.context7-mcp and confirmed it ships exactly the
  shape this PR adopts (just stdio instead of http).

How

For each <service>/vscode/:

• package.json → contributes.mcpServerDefinitionProviders: [{id, label}]
  • commands (Set / Clear API Token) + main: ./extension.js +
    engines.vscode: ^1.101.0 (first stable release with the API; Context7
    uses the same).
• New extension.js — vanilla JS, no build step. Registers the provider
  and resolves the server with a Bearer token sourced from
  $ACEDATACLOUD_API_TOKEN, then VS Code SecretStorage, then an
  interactive showInputBox prompt as last resort. Two commands let users
  rotate or clear the stored token.
• README.md "Configuration" section rewritten to describe the new flow;
  manual mcp.json snippets demoted to alternatives.
• In-repo version bumped 0.2.0 → 0.3.0; CalVer pipeline will assign the
  real marketplace version on push to main.

scripts/build_vscode_extensions.py was updated to be the single source of
truth — re-running it reproduces all 45 changed files byte-for-byte.

Verification

$ cd suno/vscode && npx -y @vscode/vsce package --no-git-tag-version
 INFO  Files included in the VSIX:
mcp-suno-0.3.0.vsix
├─ extension/
│  ├─ LICENSE.txt
│  ├─ changelog.md
│  ├─ extension.js          [3.32 KB]
│  ├─ icon.png
│  ├─ package.json
│  └─ readme.md
 DONE  Packaged: …/mcp-suno-0.3.0.vsix (8 files, 65.74 KB)

# packaged manifest (from inside the .vsix):
main:        ./extension.js
engines:     { vscode: ^1.101.0 }
contributes: ['mcpServerDefinitionProviders', 'commands']
provider:    [{id: 'acedatacloud.suno', label: 'Suno MCP'}]

No publish-workflow changes needed: vsce package ships extension.js as
plain JS, no compile step required.

Follow-up

Once this merges, the per-service publish.yml jobs in each sub-repo will
auto-publish a fresh CalVer build (2026.<MMDD>.0) to the marketplace and
fix the 15 broken extensions currently live.