fix: register claude-code transforms so tool calls pass through

[wayniacal]

ADAPTER_TRANSFORMS has no entry for claude-code, so getAdapterTransforms("claude-code") returns [] and a Claude Code client keeps the createRequestContext defaults: blockedTools: [], passthrough: undefined. The SDK subprocess then runs the client's task itself, on the proxy host, with its own built-in Read/Write/Bash, while the CLI executes the same tool_use blocks locally. Every side effect happens twice.

claudeCodeAdapter.usesPassthrough() already returns resolvePassthrough(true), but nothing calls it. server.ts reads pipelineCtx.*. MERIDIAN_PASSTHROUGH=1 does not reach this path either.

Same class as #546, where openai had to be added to the transform's adapters array for the same reason.

How it surfaced

A scheduled agent on 1.57.0 that edits a git repo and posts a summary through an HTTP API. One run produced three posts:

12:02:10.431  post A   CLI executed the post command
12:02:10.444  post B   SDK subprocess ran the identical command, 13 ms later
12:02:17.383  post C   second SDK session, its own wording

Proxy log for that run:

[PROXY] 4ab4f7fb adapter=claude-code model=opus[1m] tools=27 lineage=new session=new
[PROXY] 652b45ff adapter=claude-code model=opus[1m] tools=0  lineage=new session=new

652b45ff is the CLI's tools=0 structured-output request (conversation title). With no transform, that one also became a full agent with built-in tools, so it did the entire task independently: its own file edits, its own commits, a racing push to the same branch. Its transcript records it reading the other session's concurrent edits and concluding a linter had reformatted the file, then deleting 21 lines to "dedupe". It emitted the title at the end, after the side effects.

Anything a Claude Code client does through Meridian is currently doubled this way. Writes, commits, HTTP calls.

Fix

transforms/claudecode.ts mirrors claudeCodeAdapter, registered under adapter.name ("claude-code", not "claudecode"). Core tool names stay PascalCase, since Claude Code's toolkit is Read/Write/Edit/Bash/Glob/Grep; reusing openCodeTransforms verbatim would hand the deferral logic OpenCode's lowercase names and defer the tools it means to load eagerly.

Tests

Parity suite extended for claude-code, including a check that the registry entry exists at all, since that is the failure here rather than a wrong value. Full suite passes (2106 + the isolated files, 0 failures).

Verified against the live proxy with an agent asked to append one line to a file:

before   2 lines written, meridian-side session tool calls: {'Bash': 1, …}
after    1 line written,  meridian-side session tool calls: {'mcp__oc__Bash': 1}
         [PROXY] deferred=23/27 tools (core: Read,Write,Edit,Bash,Glob,Grep)