Config: nested .opencode directory configs merged in wrong precedence order (farther directory overrides nearer)

Description

ConfigPaths.directories() merges nested .opencode configs in an order that
lets farther directories override nearer ones — contradicting both the docs and
its sibling code path.

The docs state the intended precedence (docs/config.mdx, "Precedence order"):
later sources override earlier ones, "project configs can override global
defaults", and among multiple levels the natural reading is nearest-wins.
Consistent with that, ConfigPaths.files() explicitly reverses its walk result
(config/paths.ts:20) so the nearest opencode.json wins when merged in list
order (config.ts:407-409).

But directories() (paths.ts:23-41) has no such reversal. It returns project
.opencode dirs nearest-first plus ~/.opencode last, and the merge loop
(config.ts:424-433) merges them after the files() batch with later-wins, so:

1. <root>/.opencode/opencode.json silently overrides
   <root>/packages/app/.opencode/opencode.json when running from
   packages/app — the opposite of what files() does for the same nesting.
2. ~/.opencode/opencode.json is merged after every project .opencode dir,
   overriding all of them.

Reproduced on current dev:

repo/.opencode/opencode.json              { "model": "ROOT/claude-sonnet-4-5" }
repo/packages/app/.opencode/opencode.json { "model": "NESTED/gpt-4o" }

cd repo/packages/app && opencode debug config resolves to
"model": "ROOT/claude-sonnet-4-5". Per the documented precedence the nested
value should win.

The same ordering also feeds command/agent/plugin discovery
(config.ts:459-465) and tui-migrate.ts, so those inherit the inverted
precedence too.

If the documented order is the intent, the fix is likely one .toReversed() on
the project portion of directories() (plus deciding where ~/.opencode
belongs relative to project dirs). Happy to send a PR with nested-case tests if
the expected precedence is confirmed.

Plugins

No response

OpenCode version

dev + manually reproduced (opencode debug config)

Steps to reproduce

1. mkdir -p repo/.opencode repo/packages/app/.opencode
2. echo '{ "$schema": "https://opencode.ai/config.json", "model": "ROOT/claude-sonnet-4-5" }' > repo/.opencode/opencode.json
3. echo '{ "$schema": "https://opencode.ai/config.json", "model": "NESTED/gpt-4o" }' > repo/packages/app/.opencode/opencode.json && git init repo
4. cd repo/packages/app && opencode debug config
5. Output shows the ROOT model; per documented precedence it should show the NESTED one

Screenshot and/or share link

No response

Operating System

Windows 11 (platform-independent)

Terminal

Windows Terminal