fix: resolve the OpenClaw state dir consistently (md-mirror workspace map, CLI and workspace defaults)

[gorkem2020]

Problem

The plugin assumed a single OpenClaw instance living at ~/.openclaw:

• resolveAgentWorkspaceMap (md-mirror) only read the legacy agents.list array. OpenClaw 2026.9 writes the keyed agents.entries form, so the mirror logged mdMirror: no agent workspaces found and wrote every agent's mirror into the default directory.
• When the runtime config carried no agents, the fallback read ~/.openclaw/openclaw.json. On a host running a second instance (OPENCLAW_STATE_DIR pointing elsewhere) that is another instance's config; the observed effect was the second instance's mirror landing inside the first instance's main-agent workspace.
• The default db, workspace and md-mirror directories, the CLI --openclaw-home default and OAuth file path, and the workspace capability default were all rooted at homedir()/.openclaw regardless of OPENCLAW_STATE_DIR.

Change

• src/openclaw-paths.ts: one resolver. State dir = OPENCLAW_STATE_DIR, then OPENCLAW_HOME, then ~/.openclaw; config path = OPENCLAW_CONFIG_PATH, then <state dir>/openclaw.json. Blank or whitespace-only values count as unset.
• The md-mirror workspace map reads both agents.entries (keyed) and agents.list (array), from the runtime config first and from the resolved config file second.
• Plugin defaults, the CLI and the workspace capability default all go through the resolver. Single-instance installs resolve to exactly the same paths as before, so there is no behaviour change for the default layout.

Tests

• test/openclaw-paths.test.mjs: precedence and blank-variable handling.
• test/mdmirror-workspace-map-entries.test.mjs: entries form, list form, OPENCLAW_CONFIG_PATH fallback, state-dir fallback, state-dir-rooted and home-rooted defaults.
• Both are registered in the npm test chain and in scripts/ci-test-manifest.mjs (core-regression). Full suite, core-regression, cli-smoke, packaging-and-workflow and verify-package-runtime are green locally; dist is rebuilt and committed.

Verification on a live install

Running as a hotfix on a seven-agent OpenClaw 2026.9.2 install: the startup log went from mdMirror: no agent workspaces found to mdMirror: resolved 7 agent workspace(s), and mirror files land in each agent's own workspace.