feat(desktop): allow configuring dev remote-debugging-port; chore(opencode): add --no-minify flag to build script

[CannonRS]

Issue for this PR

Closes #46194
Closes #46195

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Two small CLI / dev-quality knobs, one commit each, both product-neutral:

Commit 1 — chore(opencode): add --no-minify flag to build script (packages/opencode/script/build.ts)

The CLI build script already accepted --sourcemaps, --single, --baseline,
--skip-install, --skip-embed-web-ui. It did not have a way to opt out of
minification for local debugging or for bun run smoke tests, which is annoying
when a regression only reproduces against the unminified bundle (e.g. readable
stack traces, exact symbol names). This adds --no-minify as a sibling flag and
turns minify: true into minify: !noMinifyFlag. Default behaviour is unchanged.

Commit 2 — feat(desktop): allow configuring dev remote-debugging-port (packages/desktop/src/main/index.ts)

In unpackaged/dev runs the desktop main process pins the Electron remote
debugging port to "9222". If the developer's local port 9222 is already in
use (common when several Electron apps, VS Code, or another opencode desktop
dev build are running) the second instance silently fails to expose the
DevTools. This reads process.env.OPENCODE_REMOTE_DEBUGGING_PORT and falls back
to "9223" (the desktop's preferred dev port, one above the OS-default
9222). The new env var is opt-in: existing dev setups that already free 9222
or override it through --remote-debugging-port directly keep working.

How did you verify your code works?

• Two commits, one file each:
  • packages/opencode/script/build.ts +2/-1
  • packages/desktop/src/main/index.ts +4/-1
• bun typecheck passes in both packages (tsgo --noEmit exit 0 in
  packages/opencode, tsgo -b exit 0 in packages/desktop) after bun install --ignore-scripts in the worktree, against upstream/dev head
  dc4449df0d plus both commits.
• Manually traced both call sites:
  • build.ts: the new noMinifyFlag is read once at module top, mirroring
    sourcemapsFlag/singleFlag/baselineFlag; the only minify: literal in
    the per-target loop is replaced with the new expression.
  • index.ts: the if (!app.isPackaged) ... appendSwitch("remote-debugging-port", "9222")
    block was a single line; it is now a block that reads the env var with a
    default. Nothing else in the file touches this switch.

Screenshots / recordings

N/A — no UI change.

Checklist

• I have tested my changes locally
  • bun typecheck in packages/opencode and packages/desktop both pass
    after bun install --ignore-scripts in the worktree, against
    upstream/dev head dc4449df0d plus both commits.
• I have not included unrelated changes in this PR