fix: token substitution in OPENCODE_CONFIG_CONTENT

[ariane-emory]

What does this PR do?

• Route inline config through load() function to enable {env:} and {file:} token substitution
• Make OPENCODE_CONFIG_CONTENT a dynamic getter for runtime env var access
• Add tests for {env:} and {file:} token substitution in OPENCODE_CONFIG_CONTENT

Fixes #13219

How did you verify your code works?

Manual testing, bun typecheck, bun test.

You may manually test by running commands akin to the following (assuming bash):

echo "matrix" > /tmp/test-secret.txt 
export MODEL="opencode/big-pickle"
OPENCODE_CONFIG_CONTENT='{"$schema":"https://opencode.ai/config.json","theme":"{file:/tmp/test-secret.txt}", "model":"{env:MODEL}"}' bun dev

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential Duplicate Found

PR #13226: fix(config): apply token substitution for OPENCODE_CONFIG_CONTENT
#13226

This appears to be a closely related or duplicate PR addressing the same issue. Both PRs:

• Target token substitution in OPENCODE_CONFIG_CONTENT
• Handle {env:} and {file:} token substitution
• Are related to the same issue (OPENCODE_CONFIG_CONTENT bypasses {env:} and {file:} token substitution #13219)

You may want to review PR #13226 to determine if it's been merged or if there's overlap in the implementation.

[remixz]

@rekram1-node unfortunately i think this is causing a regression, we use this env var for inspect and on 1.1.64 it's writing OPENCODE_CONFIG_CONTENT as a file to the root directory :(

[rekram1-node]

Ofc :/

[ariane-emory]

@remixz Can you provide any further details on the problem? I'm not entirely sure precisely what you mean by f'or inspect'? I'd like to investigate and come up with a fix.

[remixz]

@ariane-emory for sure! for context, i work at ramp, where we have our own coding agent called Inspect, which is powered by opencode. i promise not an ad, but if you're curious: https://builders.ramp.com/post/why-we-built-our-background-agent

so we start the opencode server with createOpencodeServer from the V2 SDK, and pass it a config object. this change was causing it to just write a file called OPENCODE_CONFIG_CONTENT to the root directory that opencode started in. repro i think literally will be just a script like

import { createOpencodeServer } from '@opencode-ai/sdk/v2'

createOpencodeServer({ config: {} })

and you should see it just write this file to the root. so technically we don't use the env var itself, but under the hood createOpencodeServer is setting OPENCODE_CONFIG_CONTENT from the contents of the passed config object:

opencode/packages/sdk/js/src/v2/server.ts

Line 38 in 1fb6c0b

OPENCODE_CONFIG_CONTENT: JSON.stringify(options.config ?? {}),