test(tool): pin every tool's parameters schema before migration

Pre-migration safety net for the upcoming tool-by-tool zod\u2192Schema
conversion. Every tool's parameters schema now has:

1. A JSON Schema snapshot (`z.toJSONSchema` with `io: "input"`) \u2014 this
   captures exactly what the LLM sees at tool registration time, so any
   drift caused by a future migration fails the snapshot.
2. Parse-accept/parse-reject assertions per tool pinning the
   user-visible behavioural contract (required fields, refinement
   bounds, enum membership, default values).

To make the snapshots possible without standing up each tool's full
Effect runtime, every tool file now exports its parameters schema as
`Parameters` at module scope:

- 9 tools already had a module-level const \u2014 just added `export`, and
  standardised the name to `Parameters` (uppercase) where it was
  previously `parameters`.
- 9 tools had their schema inline inside `Tool.define` \u2014 hoisted to
  module scope under the same `Parameters` name and wired back through.

Zero behaviour change: Tool.define still sees the same schema, runtime
validation path is identical, SDK (types.gen.ts + openapi.json) is
byte-identical, and the full 2054-test suite passes.

18 JSON Schema snapshots and 43 explicit parse/reject assertions for the
18 built-in tools (apply_patch, bash, codesearch, edit, glob, grep,
invalid, lsp, multiedit, plan, question, read, skill, task, todo,
webfetch, websearch, write).

packages/opencode/src/tool/bash.ts

@@ -50,7 +50,7 @@ const FILES = new Set([
 const FLAGS = new Set(["-destination", "-literalpath", "-path"])
 const SWITCHES = new Set(["-confirm", "-debug", "-force", "-nonewline", "-recurse", "-verbose", "-whatif"])
 
-const Parameters = z.object({
+export const Parameters = z.object({
   command: z.string().describe("The command to execute"),
   timeout: z.number().describe("Optional timeout in milliseconds").optional(),
   workdir: z